Ad Click Through Rate - Ad click throughs as a percentage of the number of impressions served.

Ad Impressions - The number of times an advertiser's banner is downloaded by users.

Ad Product - A specific advertising opportunity on a website e.g. banners, jump pages, pop-ups, splash pages and tickers.

Animated GIF - The combination of multiple GIF images in one file to create animation. The multiple images, displayed one after another, give the appearance of movement. Studies show that animated banners are more effective than static banners. They generate higher ad awareness and recall, and click-throughs.

Banner - An online advertisement in the form of a graphic image on a web page that links to a location of the advertiser's choice (e.g. the advertisers' website, promotional page, jump page, etc.). The banner is in GIF or JPEG (see GIF or JPEG) format.

Browser - any software program that lets you surf the Internet and view web pages. Microsoft Internet Explorer and Netscape Navigator are two of the most commonly used browsers.

Cache - A file on a user PC's hard disk, or corporate/Internet Service Provider (ISP) server, that stores web pages for display in the browser. This speeds up viewing because pages are downloaded to the user's computer from a local computer as opposed to having to download from the Internet.

CPM - Cost Per Thousand (Roman Numeral) impressions. The price paid by an advertiser for a site displaying their banner a thousand times. CPM is the standard web-advertising model.

Demographics- Common characteristics used for population segmentation. Typical demographic data include age, gender, occupation, and income.

Electronic Commerce (E-Commerce)- The process of selling products or services via the Web on a secured platform.

GIF (pronounced "jif") - The most common image file format on the Internet, especially for animated banners. Stands for Graphic Interchange Format. See also JPEG.

Hits- Each time a Web server sends a file to a browser, it is recorded in the server log file as a "hit". Every graphical image on a web page counts as a hit. Hits can be used to measure traffic activity on a website but it isn't the most reliable measurement when comparing different sites. E.g.: One page with 10 images will register 11 hits when viewed, while a page with no graphics will only register one hit.

HTML (HyperText Markup Language) - The standard file format for internet documents (web pages).

Hyperlink - Text or graphics that are hyperlinked will transport a user to another location of content either on the same page or another page.

Internet Service Provider (ISP) - An organisation that provides Internet access for a fee or hosting of web pages.

Interstitial Ads- Interstitial ads are ads that appear in a separate browser window while another page is loaded. If a user, on page A, clicks a hyperlink to go to page B, the user will see the interstitial ad before arriving at page B.

Inventory- The amount of available space on a website for ad banners.

JPEG (Joint Photographic Experts Group)- A graphics file format, similar to GIF, but with one difference -- there is no animation. Used more for photographs.

Jump Page - The page that is displayed when a user clicks on a banner. Can be used for just about anything from promoting a website, product or service, user registration to contests.

Link- Same as a hyperlink. When clicked on, a link brings you to another web page, or to another place on the same page.

Page Views - The number of times users request a web page. Page view is used interchangeably with page impression.

Portal - A super site that provides a wide variety of services including web searching, news, free email, entertainment, shopping and more. It's a virtual "door" that opens up to a plethora of online services. It's often the first screen that a user sees after logging on.

Rate Card- Advertising price list.

Reach- The total number of people who will see a given ad.

ROS (Run of Site)-Provides the advertiser with the opportunity to reach a broad audience by running ads throughout a website. There is, however, no specific targeting in this model.

Search Engine - A program that acts as a catalog for the Internet. Using keywords, search engines to help a user locate their desired information. Examples: Yahoo, Alta Vista, Lycos, Infoseek and Excite.

Sponsorships- Integrates an advertiser's message with content on an exclusive or non-exclusive basis. Identified by "Brought to you by..." or "Sponsored by..." messages.

Targeting- The process of delivering an advertiser's ad to the user through either content matching, profiling, or filtering.

Traffic- The number and types of people who come to a website. Measured in many different ways.

Unique Users- Users marked by either a Global User ID (GUID) or a cookie in the form of an ID that is attached to a user's browser. Unique users do not include repeat users during a specified session.

URL (Uniform Resource Locator) - The address of a website or a page of a site. It usually begins with "http://". Every file and page on the Web has a unique URL.