A GIF or JPEG image with more than one linking hyperlink. Each hyperlink or hot spot can lead to a different destination page.

A measurement of responses from a Web server to a page request from the user browser, which is filtered from robotic activity and error codes, and is recorded at a point as close as possible to opportunity to see the page by the user.

Actual placement of an ad in a document, as recorded by the ad server.

Purchase order between a seller of interactive advertising and a buyer (usually an advertiser or its agency)

Software tools which help the user find information of specific interest to him/her. The user‘s profile is continually refined and improved based on the user's acceptance or rejection of recommendations over time.