Glossary of Terminology

Note: The following definitions describe terminology as it specifically relates to interactive advertising designed for Internet websites.


Term Definition
302 Redirect The process of a server sending a browser the location of a requested ad, rather than sending the ad itself. Ad servers use 302 redirects to allow them to track activities such as ad requests or ad clicks.
3G 3G is the “Third Generation” mobile network infrastructure. As of 2007, 3G technologies were deployed by mobile operators in most of Europe, East Asia, and North America. Supports much higher data speeds than previous mobile networks, in some cases approaching wired broadband connections.

Core 3G technologies include:

  • EDGE
  • Universal Mobile Telecommunications System (UMTS)
  • CDMA2000
  • LTE
AAAA Founded in 1917, the American Association of Advertising Agencies (AAAA) is the national trade association representing the advertising agency business in the United States.
AAS Average active sessions – the average number of streams of one minute or more that are active within a time period.
Abandonment Abandonment is when a user leaves a shopping cart with something in it prior to completing the transaction.
Abort When a Web server does not successfully transfer a unit of content or ad to a browser. This is usually caused by a user hitting the stop button or clicking on another link prior to the completion of a download.
Above the Fold Above the Fold – (ATF) a term derived from newspaper print advertising, this means that an ad is placed on a website above the scroll line as the page is viewed before any scrolling occurs; in view before scrolling
Activity audit Independent verification of measured activity for a specified time period. Some of the key metrics validated are ad impressions, page impressions, clicks, total visits and unique users. An activity audit results in a report verifying the metrics. Formerly known as a count audit.
Ad audience The number of unique users exposed to an ad within a specified time period.
Ad banner Ad banners (also known as banner ads) are one of the most dominant forms of advertising on the internet. Banner ads are a form of display advertising that can range from a static graphic to full motion video.
Ad blocker Software on a user’s browser which prevents advertisements from being displayed.
Ad campaign audit An activity audit for a specific ad campaign.
Ad click The user activity of pressing a navigation button or hitting the enter key on the keyboard on an advertisement unit on a Web site (banner, button or text link). (See Click-through)
Ad creative pixel A pixel request embedded in an ad tag which calls a web server for the purpose of tracking that a user has viewed a particular ad. See web beacon.
Ad delivery Two methods are used to deliver ad content to the user – server-initiated and client-initiated, which are explained in the diagrams below.
Ad download When an ad is downloaded by a server to a user’s browser. Ads can be requested, but aborted or abandoned before actually being downloaded to the browser, and hence there would be no opportunity to see the ad by the user.
Ad exchange An ad exchange is a sales channel between publishers and ad networks that can also provide aggregated inventory to advertisers. They provide a technology platform that facilitates automated auction based pricing and buying in real-time. Ad exchanges’ business models and practices may include features that are similar to those offered by ad networks. For the purposes of the IAB Networks & Exchanges Quality Assurance Guidelines, the definition of an ad exchange excludes technology platforms that exclusively provide tools that enable direct media buying and selling between exchange participants.
Ad family A collection of one or more ad creatives. Also called an ad campaign.
Ad impression Ad impressions are the count of ads which are served to a user. Ads can be requested by the user’s browser (referred to as pulled ads) or they can be pushed, such as e-mailed ads. In a formal sense, ad impressions are a measurement of responses from an ad delivery system to an ad request from the user’s browser, which is filtered for robotic activity and is recorded at a point as late as possible in the process of delivery of the creative material to the user’s browser — therefore closest to the actual opportunity to be seen by the user.
Two methods are used to deliver ad content to the user:

  • Server-initiated. The publisher’s web content server for making requests, formatting and re-directing content.
  • Client-initiated. Ad counting relies on the user’s browser to perform these activities.

For organizations that use a server-initiated ad counting method, counting should occur subsequent to the ad response at either the publisher’s ad server or the Web content server. For organizations using a client-initiated ad counting method, counting should occur at the publisher’s ad server or third-party ad server, subsequent to the ad request, or later, in the process.

Ad impression ratio Click-throughs divided by ad impressions. See click rate.
Ad insertion When an ad is inserted in a document and recorded by the ad server.
Ad inventory The aggregate number of opportunities near publisher content to display advertisement to visitors.
Ad materials The creative artwork, copy, active URLs and active target sites which are due to the seller prior to the initiation of the ad campaign.
Ad network Ad networks provide an outsourced sales capability for publishers and a means to aggregate inventory and audiences from numerous sources in a single buying opportunity for media buyers. Ad networks may provide specific technologies to enhance value to both publishers and advertisers, including unique targeting capabilities, creative generation, and optimization. Ad networks’ business models and practices may include features that are similar to those offered by ad exchanges.
Ad Ops The team/function that is responsible for trafficking and optimizing digital ad campaigns.
Ad recall A measure of advertising effectiveness in which a sample of respondents is exposed to an ad and then at a later point in time is asked if they remember the ad. Ad recall can be on an aided or unaided basis. Aided ad recall is when the respondent is told the name of the brand or category being advertised.
Ad request The request for an advertisement as a direct result of a user’s action as recorded by the ad server. Ad requests can come directly from the user’s browser or from an intermediate Internet resource, such as a Web content server.
Ad server An ad server is a web server dedicated to the delivery of advertisement. This specialization enables the tracking and management of advertising related metrics.
Ad serving The delivery of ads by a server to an end user’s computer on which the ads are then displayed by a browser and/or cached. Ad serving is normally performed either by a Web publisher or by a third-party ad server. Ads can be embedded in the page or served separately.
Ad space The location on a page of a site in which an advertisement can be placed. Each space on a site is uniquely identified. Multiple ad spaces can exist on a single page.
Ad stream The series of ads displayed by the user during a single visit to a site (also impression stream).
Ad tag Software code that an advertiser provides to a publisher or ad network that calls the advertisers ad server for the purposes of displaying an advertisement.
Ad targeting Delivering an ad to the appropriate audience. This may be done through:

  • Behavioral Targeting
  • Contextual Targeting
  • Geographic Targeting
Ad transfers The successful display of an advertiser’s Web site after the user clicked on an ad. When a user clicks on an advertisement, a click-through is recorded and re-directs or “transfers” the user’s browser to an advertiser’s Web site. If the user successfully displays the advertiser’s Web site, an ad transfer is recorded.
Ad unit An ad or set of ads displayed as a result of a piece of ad code executing.


Ad view When the ad is actually seen by the user. Note this is not measurable today. The best approximation today is provided by ad displays.
Add to cart The user activity of storing merchandise in a virtual shopping cart that the user intends to later purchase from an online e-commerce website. This enables users to continue browsing and “check-out” later or alternately delete these items from the cart.
Address A unique identifier for a computer or site online, usually a URL for a Web site or marked with an @ for an e-mail address. Literally, it is how one computer finds the location of another computer using the Internet.
Advertisement A commercial message targeted to an advertiser’s customer or prospect.
Advertiser The company paying for the advertisement.
Adware Computer software provided to the user free of charge or at a discounted price that downloads and displays advertising to support its continued development and maintenance. This software often tracks what Internet sites the user visits.
Affiliate marketing An agreement between two sites in which one site (the affiliate) agrees to feature content or an ad designed to drive traffic to another site. In return, the affiliate receives a percentage of sales or some other form of compensation generated by that traffic.
Affinity marketing Selling products or services to customers on the basis of their established buying patterns. The offer can be communicated by e-mail promotions, online or offline advertising.
Agency An organization that, on behalf of clients, plans marketing and advertising campaigns, drafts and produces advertisements, places advertisements in the media. In interactive advertising, agencies often use third party technology (ad servers) and may place advertisements with publishers, ad networks and other industry participants.
Agency Ad Server The ad server hosted by the advertising agency.
Aggregate Campaign Data Data combined from several advertising campaigns to create a segment where campaign level data is not identifiable.
Alternate text A word or phrase that is displayed when a user has image loading disabled in their browser or when a user abandons a page by hitting “stop” in their browser prior to the transfer of all images.Also appears as “balloon text” when a user lets their mouse rest over an image.
ANA The Association of National Advertisers (ANA) leads the marketing community by providing its members insights, collaboration and advocacy. The ANA strives to promote and protect all advertisers and marketers. See ANA.net for more information.
Animated GIF An animation created by combining multiple GIF images in one file. The result is multiple images,displayed sequentially, giving the appearance of movement.
Animation A programmatically generated display of sequential images, creating the illusion that objects in the image are moving. Not digital video, as it relates to this document (see the definition for “Video”).
Anonymizer An intermediary which prevents Web sites from seeing a user’s Internet Protocol (IP) address.
API An API (Application Programming Interface) is a set of commands, the language that programmers or developers use to communicate with a specific piece of software or hardware. (source: http://www.iab.net/mraid)
Applet A small, self-contained software application that is most often used by browsers to automatically display animation and/or to perform database queries requested by the user.
Applicable Browser Any browser an ad will impact, regardless of whether it will play the ad.
Apps Short for “applications”, these are programs on a digital device (most commonly smartphones and tablets) that provide a specific service or function; usually will connect to the internet and can be ad-supported/free or paid.
ARF The ARF (Advertising Research Foundation) is the premiere advertising industry association for creating, aggregating, synthesizing and sharing the knowledge required by decision makers in the field. The principal mission of The ARF is to improve the practice of advertising, marketing and media research in pursuit of more effective marketing and advertising communications. See the ARF
Artifacting Distortion that is introduced into audio or video by the compression algorithm (codec). Compressed images may have stray pixels that were not present in the original image. See codec.
Aspect Ratio The width-to-height ratio of a picture or video frame. TV broadcasts at a 4:3 (1.33:1) aspect ratio; digital TV will be broadcast with a 16:9 (1.78:1) ratio; and most feature films are shot in at least a 1.85:1 ratio. IMUs have an aspect ratio of 6:5 (330x 250; 336 x 280; and 180 x 150).
Assets Logos, artwork, fonts, etc. that a brand uses in their advertising creative.
Association of National Advertisers The Association of National Advertisers (ANA) leads the marketing community by providing its members insights, collaboration and advocacy. The ANA strives to promote and protect all advertisers and marketers. See ANA.net for more information.
Attribute A single piece of information known about a user and stored in a behavioral profile which may be used to match ad content to users. Attributes consist of demographic information (e.g., age, gender, geographical location), segment or cluster information (e.g., auto enthusiast), and retargeting information (e.g., visited Site X two days ago). Segment or cluster information is derived from the user’s prior online activities (e.g., pages visited, content viewed, searches made and clicking and purchasing behaviors). Generally, this is anonymous data (non-PII).
Attribution The process of connecting an ad event to a consumer action; or, more broadly, the process of connecting any consumer touchpoint a brand provides to a desired response.
Audience An audience is the group of people who visit a specific web site or who are reached by a specific ad network.
Audience Measurement The counting of unique users (i.e. audience) and their interaction with online content. At a campaign level, this service is conducted by a third party to validate that a publisher delivered what an advertiser had requested. At the industry level, this service enables media buyers to understand which brokers of online content to negotiate with to reach a specific audience.
Audience Targeting A method that enables advertisers to show an ad specifically to visitors based on their shared behavioral, demographic, geographic and/or technographic attributes. Audience targeting uses anonymous, non-PII data.
Audio The audible file that may accompany ads. Advertising audio should not play without user-initiation in general. See detailed IAB New Ad Portfolio guidance for when it can be played without user initiation.
Audit Third party validation of log activity and/or measurement process associated with Internet activity/advertising. Activity audits validate measurement counts. Process audits validate internal controls associated with measurement.
Auditor A third party independent organization that performs audits.
Authenticated viewing When cable networks provide services where their customers can access television content online after logging in through a host site.
Avatar A graphical representation of an individual in a game or other virtual world or environment.
Average active sessions The average number of streams of one minute or more that are active within a time period.
Average view time Refers to the average amount of time the video ad was played by users.
Backbone High-volume, central, generally “long-haul” portion of a data network.
Bandwidth The transmission rate of a communications line or system, expressed as kilobits per second (kbps) or megabits per second (Mbps) for digital systems; the amount of data that can be transmitted over communications lines in a given time.
Bandwidth contention A bottleneck that occurs when two or more files are simultaneously transmitted over a single data line. Unless the system is able to prioritize among the files, the effect is to slow delivery of each.
Banner Also known as “display ads”, banner advertisements are a form of graphical ads embedded into a webpage, typically including a combination of static/animated images, text and/or video designed to convey a marketing message and/or cause the user to take an action. Banner dimensions are typically defined by width and height, represented in pixels.
Barter The exchange of goods and services without the use of cash. The value of the barter is the dollar value of the goods and services being exchanged for advertising. This is a recognized form of revenue under GAAP (Generally Accepted Accounting Principles).
Beacon A web beacon, also known as a web bug, 1 by 1 GIF, invisible GIF, and tracking pixel, is a tiny image referenced by a line of HTML or a block of JavaScript code embedded into a web site or third party ad server to track activity.

The image used is generally a single pixel that is delivered to the web browser with HTML instructions that keep it from affecting the web site layout. The web beacon will typically include user information like cookies on the HTTP headers, and web site information on the query string.

Web beacons are used to collect data for web site and ad delivery analytics, and also specific events such as a registration or conversion:

  • Ad Creative Pixel – A web beacon embedded in an ad tag which calls a web server for the purpose of tracking that a user has viewed a particular ad.
  • Conversion Pixel – A web beacon that transmits to a third-party server that a user has successfully completed a process such as purchase or registration.
  • Piggyback Pixel – A web beacon that embeds additional web beacons not directly placed on the publisher page.
  • Secure Pixel – A web beacon that is delivered over HTTPS.
Behavioral event A behavioral event is a user-initiated action which may include, but is not limited to: searches, content views, clicks, purchases, and form-based information.

They are generally anonymous and do not include personally identifiable information (PII).

Behavioral targeting Using previous online user activity (e.g., pages visited, content viewed, searches, clicks and purchases) to generate a segment which is used to match advertising creative to users (sometimes also called Behavioral Profiling, Interest-based Advertising, or online behavioral advertising). Behavioral targeting uses anonymous, non-PII data.
Below the Fold Below the Fold – (BTF) a term derived from newspaper print advertising, this means that an ad is placed on a website below the scroll line as the page is viewed before any scrolling occurs; out of view before scrolling
Beta A test version of a product, such as a Web site or software, prior to final release.
Between-the-Page Also known as “interstitial” ads, between-the-page ad units display as a user navigates from one webpage to the next webpage. The ad appears after the user leaves the initial page, but before the target page displays on the user’s screen. The ad is self-contained within its own browser window and may not appear as an overlay on the target page content.
Billboard An IAB Universal Brand Package ad unit template designed with options for rich interactivity to display prominently inline with Publishers’ webpage content. A distinct feature of the Billboard is a close button that a user may click to collapse the ad completely if the user doesn’t want to see the ad.
Bitrate The rate of bits processed per unit of time, commonly measured in bits per second (bps), kilobits per second (Kbps), or megabits per second (Mbps). The bitrate is one of the biggest factors in audio or video quality.
Blog A blog (a portmanteau of the term web log) is a web-published journal consisting of discrete entries (“posts”) typically displayed in reverse chronological order so the most recent post appears first. Blogs are usually the work of a single individual, although corporate blogs often have multiple staff contributors. Blog can also be used as a verb, meaning to maintain or add content to a blog.

The emergence of blogging has been attributed to the advent of easy to use web publishing tools like Open Diary, LiveJournal, and Blogger.com. The modern blogging landscape includes advanced and customizable blogging platforms like WordPress, Movable Type, and Drupal.

Successful blogs tend to focus on one topic, building a community of interested readers who interact through comments on posts. This targeted, engaged audience can drive additional value to advertisers, both during traditional campaigns and through sponsored content.

Visit the IABlog to see blogging in action!

Blog Metrics There are two concepts that surface when targeting media plans to blogs: conversations and conversation phrases. A conversation is a collection of authors/sites and their audience linked by relevant content. A conversation phrase is a combination of keywords and keyword phrases used to associate an author/site, its content and audiences to a conversation.
Bonus impressions Additional ad impressions above the commitments outlined in the approved insertion order.
Bot Software that runs automatically without human intervention. Typically, a bot is endowed with the capability to react to different situations it may encounter. Two common types of bots are agents and spiders. Bots are used by companies like search engines to discover Web sites for indexing. Short for “robot.”
Bounce See E-mail bounce.
Bounce rate Figured as a percentage, this compares the number of visitors to a website who arrive and immediately leave vs. those who stay and spend time on the site; can be used to measure the effectiveness of a website, a search campaign or an ad campaign.
Brand Awareness Research studies can associate ad effectiveness to measure the impact of online advertising on key branding metrics.
Brand metrics Measurable KPIs associated with branding objectives, such as brand lift, affinity, or favorability.
Broadband An Internet connection that delivers a relatively high bit rate – any bit rate at or above 256 Kbps. Cable modems and DSL all offer broadband connections.
Broadband Video Commercials TV-like advertisements that may appear as in-page video commercials or before, during, and/or after a variety of content in a player environment including but not limited to, streaming video, animation, gaming, and music video content. Broadband video commercials may appear in live, archived, and downloadable streaming content.
Browser A software program that can request, download, cache and display documents available on the World Wide Web.
Browser sniffer Software that detects capabilities of the user’s browser (looking for such things as Java capabilities, plug-ins, screen resolution, and bandwidth).
BtoB/B2B (Business-to-Business) Businesses whose primary customers are other businesses.
BtoC/B2C (Business-to-Consumer) Businesses whose primary customers are consumers.
Buffering When a streaming media player temporarily stores portions of a streaming media (e.g., audio or video) file on a client PC until there is enough information for the stream to begin playing.
Bug A persistent, graphical element that appears in the video environment. Clicking on it will take the user to a website.
Bulk E-mail Folder See Junk E-mail Folder.
Bumper Ad Usually refers to a linear video ad with clickable call-to-action; format is usually shorter than full linear ads (i.e. 3-10 seconds) and call-to-action usually can load another video or can bring up a new site while pausing the content.
Business Visitor A user that accesses online content in furtherance of their employment.
Button 1) clickable graphic that contains certain functionality, such as taking one someplace or executing a program; 2) buttons can also be ads. See the IAB’s Ad Unit Guidelines for voluntary guidelines defining specifications of button ads.
Button 2 A small rectangular standard ad unit with the size 120×60 pixels.
Byte A unit of digital information in computing and telecommunications that most commonly consists of eight bits. Historically, a byte was the number of bits used to encode a single character of text in a computer and for this reason it is the basic addressable element in many computer architectures.
Cable modem A device that permits high speed connectivity to the Internet over a cable television system.
Cache Memory used to temporarily store the most frequently requested content/files/pages in order to speed its delivery to the user. Caches can be local (i.e. on a browser) or on a network. In the case of local cache, most computers have both memory (RAM), and disk (hard drive) cache.
Cache busting The process by which sites or servers serve content or HTML in such a manner as to minimize or prevent browsers or proxies from serving content from their cache. This forces the user or proxy to fetch a fresh copy for each request. Among other reasons, cache busting is used to provide a more accurate count of the number of requests from users.
Cached ad impressions The delivery of an advertisement to a browser from local cache or a proxy server’s cache. When a user requests a page that contains a cached ad, the ad is obtained from the cache and displayed.
Caching The practice of temporarily storing files on local servers for quick retrieval the next time the file is needed. Cached files supply an old copy that may not be up to date with the file stored at the original source, but are often necessary for improving page load performance.
Campaign The advertising period in which an ad delivery strategy is executed.
CARU The Children’s Advertising Review Unit – Division of the Council of Better Business Bureaus that reviews advertising and promotional material directed at children in all media. See CARU for more information.
CDN An acronym for Content Distribution Network, a CDN is a system of geographically dispersed servers used to provide web content to a browser or other client. Files are strategically pulled from a server on the network based on the location of the user, the requesting server, and the delivery server of the CDN to provide the best delivery performance.
CGI script Common Gateway Interface – CGI’s are used to allow a user to pass data to a Web server, most commonly in a Web-based form. Specifically, CGI scripts are used with forms such as pull-down menus or text-entry areas with an accompanying submit button. The input from the form is processed by a program (the CGI script itself) on a remote Web server.
Chat Online interactive communication between two or more people on the Web. One can “talk” in real time with other people in a chat room, typically by typing, though voice chat is available.
Chat room An area online where people can communicate with others in real-time.
CLEAR Ad Notice CLEAR is an acronym for “Control Links for Education and Advertising Responsibly,” a set of technical guidelines developed by the Interactive Advertising Bureau (IAB) and the Network Advertising Initiative (NAI) to empower members of the online advertising community to communicate their presence and behavioral advertising targeting practices (if any) to consumers in a simple and direct manner. Derived from: https://www.iab.com/media/file/CLEAR_Ad_Notice_Final_20100408.pdf
Click An interaction between a website visitor and the browser in which the website visitor uses a device, such as a mouse, to move the cursor (or pointer) to an active area of the screen and then deliberately interacts with that area by clicking a button on their device, triggering an event. In the case of touch-screen devices, the user “clicks” by touching the active area with their finger or a stylus.
Click Fraud Click fraud is a type of internet crime that occurs in pay per click online advertising when a person, automated script, or computer program imitates a legitimate user of a web browser clicking on an ad, for the purpose of generating a charge per click without having actual interest in the target of the ad’s link.
Click rate Ratio of ad clicks to ad impressions.
Click through rate Click through rate – (CTR) the percentage of ad impressions that were clicked on as compared to the entire number of clicks [CTR% = (Clicks ÷ Imps) x 100]
Click-stream 1) the electronic path a user takes while navigating from site to site, and from page to page within a site; 2) a comprehensive body of data describing the sequence of activity between a user’s browser and any other Internet resource, such as a Web site or third party ad server.
Click-through The measurement of a user clicking on a link that re-directs the user’s web-enabled device to another Web destination.
Click-within Similar to click down or click. But more commonly, click-withins are ads that allow the user to “drill down” and click, while remaining in the advertisement, not leaving the site on which they are residing.
Clickstream Data A Clickstream is the recording of what a computer user clicks on while web browsing. As the user clicks anywhere in the webpage or application, the action is logged on a client or inside the web server, as well as possibly the web browser and ad servers. Clickstream data analysis can be used to create a user profile that aids in understanding the types of people that visit a company’s website, or predict whether a customer is likely to purchase from an e-commerce website.
Client A client can refer to either a computer or a software program running on a computer that contacts a server over a network, generally the Internet. A client typically establishes connections to servers in response to activities or configurations made by a human operator.

Internet Explorer and other web browsers, Microsoft Outlook and other e-mail programs are all examples of software clients.

Client side Client side refers to activities taking place on the client as opposed to on the server. Examples are client side counting and client side redirects.
Client-initiated ad impression One of the two methods used for ad counting. Ad content is delivered to the user via two methods – server-initiated and client-initiated. Client-initiated ad counting relies on the user’s browser for making requests, formatting and re-directing content. For organizations using a client-initiated ad counting method, counting should occur at the publisher’s ad server or third-party ad server, subsequent to the ad request, or later, in the process. See server-initiated ad impression.
Close X A creative control that enables a user to close an ad (remove it from view) or to reduce an expanded panel back to its original size.
Cloud A term used by web-based companies offering users the ability to access files or services from devices that are connected to the internet (the opposite of storing files or programs on a hard or external drive).
Collapse An event where the expanded panel of an expandable ad reduces to its original size, or disappears completely.
Compression The practice of packaging a digital file so that it uses less storage space.
Controls Active elements of an ad that enable a user to control the advertising experience. Examples of common controls include the “Close X” button in an expandable ad or the Play/Pause/Mute buttons in a video player.
CPU CPU is an acronym for Central Processing Unit, the key component of a computer system, which contains the circuitry necessary to interpret and execute program instructions.
CPU Usage % A guideline for the amount of central processing power used to display advertising content compared to what’s available on an individual’s computer. CPU usage percentage can be measured directly, during the execution of an online ad. In addition to file size, the complexity of drawings, gradients, slow moving animations and detailed moving elements can affect the number of calculations the CPU must make for each frame.
CPU Spike A brief increase in central processing power, sustained for no more than a few seconds, experienced while “heavy” content is loaded/executed.
Creative An advertising unit created by an ad designer, in accordance with publisher specifications and guidelines, for the purpose of communicating a marketing message to that publisher’s audience. One creative may consist of multiple files in various formats, such as standard images, animation, video, execution files (.html, .js, etc.) and other files that work together for an interactive experience.
Creative Dimensions Measured in pixels, the width and height of an ad unit (WxH). The width is always the first dimension listed, followed by the height dimension (i.e. an ad that is 300×250 is 300 pixels wide by 250 pixels high).
Cursor The graphical representation of a “pointer” on a user screen, controlled by the user’s interaction with controlling devices such as a mouse, mouse pad, stylus or other input hardware.
Expandable Ads Rich media ads that can be enlarged to dimensions beyond the initial dimensions of the placement they fill on the webpage. The user initiates expanding events, sometimes after the ad initially expands briefly on its own to catch the user’s attention.
Expanded Dimensions The secondary dimensions of an expanding ad unit (after the ad is expanded). Initial dimensions are fit to the dimensions of the placement. Then, either by auto-play or by user interaction, the ad unit expands to its secondary dimension.
File requests In the context of displaying digital content, the browser loads code that contains instructions about where to retrieve files such as text, images, videos, and any other components that contribute to the display experience. Each time the browser must retrieve content from another server, a file request is made. Too many file request may reduce page load performance.
Filmstrip An IAB Universal Brand Package ad unit template that is 350×3000 pixels, divided into five 350×600 pixel segments that scroll by user interaction though a 350×600 pixel placement “window.”
Flash™ Software and tools developed by Adobe used to build, generate, and play animated files. Also used to define the creative files generated by the program. In order for Flash files to execute in a browser, the Flash player plug-in must be installed. However, Flash development tools can also generate files in HTML5 format so that no plug-in is required for execution.
FPS FPS is an acronym for Frames Per Second, the metric used to indicate the frame rate of animated or video creative content.
Frame Rate The rate at which video frames or animated images display as the video or animated file executes, measured as the number of frames per second (fps).
GPU GPU is an acronym for Graphics Processing Unit. In modern computers, the GPU handles graphical processing, decreasing the processing burden handled by the CPU.
Gzip Automatic compression of creative assets for an ad when delivering from an ad server to a web page or application. The key difference between .zip files and gzip is that zip is used for storing files, and gzip is used for compressing files that are in transmission from one server to another.
H.264 A video coding format that uses a block-oriented, motion-compensation-based video compression standard. H.264/MPEG-4 AVC is one of the most common formats used for recording, compressing, and distributing video content.

For more information see: https://en.wikipedia.org/wiki/H.264/MPEG-4_AVC

HLS An acronym for HTTP Live Streaming is an HTTP-based media streaming communications protocol implemented by Apple Inc. It works by breaking the overall stream into a sequence of small HTTP-based file downloads, each download loading one short chunk of an overall potentially unbounded transport stream. As the stream is played, the client may select from a number of different alternate streams containing the same material encoded at a variety of data rates, allowing the streaming session to adapt to the available data rate. At the start of the streaming session, it downloads an extended M3U playlist containing the metadata for the various sub-streams [that] are available. See http://en.wikipedia.org/wiki/HTTP_Live_Streaming for more information.
Host-initiated Any activity that is auto-initiated.
Host-initiated sub-load The additional file limit allowed that is auto-initiated after the load event is fired by the window object of the publisher page (intial web page content has been loaded) on the host computer or device. In absence of access to publisher page window object, the window object of the ad iframe can be used.
Hot Spot A “hot spot” is an area of an ad unit, which when rolled-over/rolled-on by the user’s cursor, such rollover triggers an event (i.e. expand ad). The hotspot should never be larger than 1/4th the size of the original (collapsed) ad unit. The trigger event should not occur unless the user’s cursor rests in the hotspot zone for at least 1-second. Hotspots should never initiate audio (audio should only be initiated by a click). When hotspots are used, the trigger event should stop immediately upon the user’s cursor leaving the hotspot zone (i.e. ad collapses), and the ad unit should return to its original state.
HTML5 An acronym for Hypertext Markup Language, version 5. HTML5 extends earlier versions to include tags for processing video, audio, canvas, an other embedded audio and video items without requiring proprietary plug-ins and APIs. HTML5 has been used as an alternative to developing and executing interactions similar to those using Adobe Flash but with very different technology.
IBA Interest-based advertising — which is also sometimes called “online behavioral advertising” — uses information gathered about a site user’s visits over time and across different websites or applications in order to help predict preferences and show ads that are more likely to be of interest to you. For example, a sporting goods manufacturer might work with an advertising network that collects and uses interest-based advertising information to deliver ads to the browsers of users that have recently visited sports-related sites, or an airline might direct ads to users that recently visited mobile travel apps. Definition from aboutads.info site: http://www.aboutads.info/how-interest-based-ads-work
In-Banner Video A video delivered as part of (inside of) the display ad creative for a given placement rather than initiating the use of a video player.
Initial Dimension The original width and height (in pixels) of an expanding ad. Expanding ads are designed to expand to dimensions larger than the initial dimensions.
Initial File Load Includes all assets and files necessary (.html, .js, .css, .woff, images, ets.) for completing first visual display of the Ad. The initial file load size of an ad is limited in order to preserve the page load performance and thus the user’s web browsing experience. For non-rich media ads, the initial file load size limit is all that’s allowed for the ad.
Interstitial See ‘Between-the-Page’
JavaScript libraries A collection of pre-written code used to simplify development of web-based applications.
Kilobyte (KB) A multiple of the unit ‘byte’ for digital information, used to quantify computer memory or storage capacity equal to a 1,000 bytes (or technically, 2^10 = 1,024 bytes). For the purposes of this document, this measure relates to creative file size. (See definition for Byte)
Labeling Requirements The minimal requirements for distinguishing an online advertisement from regular webpage content.
Megabyte (MB) A multiple of the unit ‘byte’ for digital information, used to quantify computer memory or storage capacity equal to 1,000 kilobytes (or technically, 2^20 = 1,048,576 bytes). For the purposes of this document, this measure relates to creative file size. (See definition for Byte)
Minification The practice of removing unnecessary characters from code to reduce its size, removing unnecessary spacing, and optimizing the CSS code; thus improving load times.
moov atom A video data object in a media file used to execute the video. The moov (or movie) atom should be placed at the beginning of a video file to ensure proper execution.
Mouse-off The act of a user moving the cursor away (off) from the hot spot of an ad. Mouse-off by a user may trigger an event, such as collapsing an expanding panel or stopping any animation in progress.
Mouse-over The act of a user moving the cursor and resting it on the hot spot of an ad for at least one second. Mouse-over may trigger an event such as expanding the ad or initiating an animated sequence within the ad. Mouse-over may NOT initiate audio play.
MP4 A digital multimedia format used to store video and audio, but may also include features such as subtitles, chapter details, and other data related to the video or audio file. The filename extension for MPEG-4 files is .mp4.
MPEG A set of standards for audio and video compression and transmission established by the Moving Picture Experts Group.
MPEG-DASH An acronym for MPEG Dynamic Adaptive Streaming over HTTP. This adaptive streaming technique allows for a streaming experience using progressive download of several small chunks of video at different bitrates. An HTTP-connected video player (the client) detects the bandwidth at each chunk of time (about 3-5 seconds) and determines which quality level to download and play for the small duration allotted.
MRAID An acronym for Mobile Rich Media Ad Interface Definition. MRAID is a protocol that enables communication between an ad and a mobile application in order to execute interactions such as geolocation, ad resizing, and accelerometer functions among others.
OBA Self-Regulation See “IBA”
Overlay An ad unit that displays over the webpage content briefly when initiated.
Pause A video, animation or audio control that enables users to stop the video, animation, or audio from playing until the user is ready to resume play.
Pixel (as a unit of measure) The smallest unit of measure for graphical elements in digital imagery, used as the standard unit of measure for ad creative (i.e. 300×250 pixels). Pixels may also represent x/y coordinates relevant to a given space, such as the browser window, an application workspace or the user’s computer screen. (See also “Tracking Pixel”)
Pixel Density The number of pixels displayed on the screen within an inch (pixels per inch or PPI) or within a centimeter (pixels per centimeter or PPCM). Screen pixel density varies by device with older monitors displaying 67 – 130 PPI. Mobile devices often exceed that at 300+ PPI. Pixel density of 163 PPI is referred to as pixel density of 1 in this document.
Play A video, animation or audio control that enables a user to initiate (or avoid initiating) the video, animation or audio of an ad.
Polite file load Withholding a portion of the total ad creative file size (besides any initial file load size) from loading on a page until publisher content has loaded. With the release of the Display Creative Guidelines in 2015, polite file load has been replaced “Host-initiated subload.” See Host-Initiated Subload for definition.
Pop-up Ad Any advertising experience where visiting a website in an initial browser window initiates a secondary browser window to deliver an ad impression directly above the initial browser window.
Portrait An IAB Rising Star ad unit template that uses up to three interactive modules chosen (by the ad designer) from a variety of modular application options in a 350×1050 pixel space.
Progress Bar A video or animation control that shows users the progression of the video or animation in relation to its total duration.
Progressive Load Video A distribution method for serving video files in which the video file downloads progressively into the cache of a user’s computer, much the same way images and other content elements are downloaded. HTML5 files use progressive download for video files, but streaming methods can be simulated using adaptive bit streaming technologies such as HLS and MPEG-DASH.
Pushdown An IAB Rising Star ad unit template designed for rich interaction in a space similar to, but larger than, an expanding leaderboard, with initial dimensions of 970×90 pixels and expanded dimensions of 970×415 pixels. When the ad is expanded, it “pushes” page content down rather than displaying over the top of page content as most expandable ads do.
Resolution The quality of an image or video file often determined by the number of pixels displayed on the screen and usually annoted as a pixel width and height dimension. However, resolution can be measured in a number of ways and takes into account pixel aspect ratio, pixel density, and other factors that determine the viewing quality of the file.
Retraction An event programmed into an expandable ad the causes the ad to be reduced to its original dimensions (i.e. the expanded portion of the ad retracts).
Rising Stars Display Ad Units IAB invited companies and individuals to submit ad templates designed to drive brand equity. Six templates were chosen to be validated by the market. Universal Brand Package Display Ad Units are designed to be the only ad on a page. Their file load limits are larger than for other ads, so not only would a Universal Brand Package Ad Unit overshadow any other ads on the page but they would also compromise the performance of the page should other rich media ads be allowed to load simultaneously. Please refer to the IAB New Ad Portfolio. The Rising Stars are in transition. They are under evaluation and will be delisted soon. Publishers should transition to the aspect ratio ad units with flexible ad sizing listed in the new ad portfolio.
Rollover  The willful pause of the user’s cursor on the target portion of the creative (the “hot spot”), such pause lasting at least one second in duration, before an action may be initiated by the ad (i.e. trigger an expand event, etc.). This one-second pause/delay requirement prevents unwanted, user-initiated actions and false reporting of user engagement. Rollover may NOT initiate audio.
Shared Libraries In digital advertising, shared libraries are collections of pre-written code and resources that are used for implementing features and functions for an HTML5 ad. Instances of such resources that are downloaded to the browser from a specific server, like a CDN, are cached on the browser. Once cached, shared libraries can be shared with other ads that reference the library and the host server.
Sidekick An IAB Rising Star ad unit template initially displayed as one of three standard ad unit dimensions, but upon user initiation, “pushes” publisher content to the left to display a canvas of up to 970×550 pixels full of rich interaction.
Skyscraper A standard ad unit with dimensions of 160×600 pixels.
Slider An IAB Rising Star Ad Unit template designed with an overlay “slider” (90 pixels high) that rests at the bottom of a publisher’s page and when prompted by user interaction, slides page content to the left for a canvas of 970×550 pixels full of rich interaction possibilities for user engagement.
Standard Ad Units A set of ad specifications for standard image or animated in-page ad units that establish a framework for advertising inventory and webpage design. The current recommended ad units are the IAB New Ad Portfolio.
Streaming Video A distribution method for serving video files such that the video is played over a persistent connection between the browser and the ad server. Versions of the file at different levels of compression (quality) can be served based on detection of the user’s Internet bandwidth. HTML5 files cannot be streamed and rely on adaptive bitrate streaming technologies such as HLS and MPEG-DASH.
Submission Lead Time The number of business days (non-weekend/non-holiday days) prior to a campaign going live in which a publisher needs to validate advertiser submitted creative(s) for a campaign.
Supporting files In the context of HTML file loads, supporting files are files that the browser needs to reference in order to execute display of file contents and any interactions. Examples of supporting files include JavaScript libraries, font libraries, CSS files, and others.
SWF Acronym for Shockwave Flash™. “.swf” is the file naming extension used for animated files complied using Adobe Flash™ software. HTML cannot execute .swf files without the browser-installed Flash player plug-in. For this reason, many content and ad providers are moving to the HTML5 format for more efficient execution of interactive media files.
Tracking Pixel A 1×1 pixel-sized transparent image that provides information about an ad’s placement. In many cases, a tracking pixel is used to notify an ad tracking system that either an ad has been served (or not served, in some cases) or that a specific webpage has been accessed. Also known as: beacon, web beacon, action tag, redirect, etc.
Universal Ad Package (UAP) A set of four ad units (728×90, 300×250, 160×600 and 180×150 pixels) offered by UAP-compliant publishers as a ‘package’ where ads in these four formats are used collectively across the publisher’s site, enabling advertisers to reach more of the publisher’s audience. Those UAP ad units are no longer recommended nor supported by IAB. They are now replaced by the IAB New Ad Portfolio.
Universal Brand Package (UBP) Display Ad Units See “Rising Stars”
User  An anonymous person who uses a web browser to access Internet web content.
User Initiation  The willful act of a user to engage with an ad. Detailed guidance is provided in the IAB New Ad Portfolio document. Users may interact by a discrete device action like clicking on the ad, and/or tapping over an ad (or a portion of an ad). Rollover is not a valid user initiation action.
Video (aka “Digital Video”) In online advertising, the digital recording of a physical event or animated files that have been transcribed into a digital video format.
Volume A control that enables users to adjust the audio output of ad creative. Volume controls should always allow adjustment down to zero (0) output.
VP8 A video compression format owned by Google and created by ON2 Technologies. Latest version is VP9.
WebM WebM is a video file format. It is primarily intended to offer a royalty-free alternative to use in the HTML5 video tag. The development of the format is sponsored by Google, and the corresponding software is distributed under a BSD license.
Z-index Enumerated layers of elements and content on a publisher’s webpage. Consideration of the z-element in page content design such as navigation, imagery, and ads is important for providing a seamless experience when page content overlaps (i.e. an expanding ad with a z-index that is lower [on the z-index scale] than navigational elements may give the appearance that page navigational elements are showing through the expanded portions of the ad).