This is a simple cookie tracking demonstration to show how a user can be tracked across many sites using a cookie. The advertising banners are downloaded from a central server that sets the “third party” cookie. “Third party” cookies mean cookies that are not placed by the web site actually being visited. The cookie from the ad server is read each time a site is visited that runs the ads. For this demonstration the banner ad is served from “track.privacy.net” and is shown in the upper frame of the page along with the cookie.
A company could track users and, if they also owned a search engine and other services where users register, an extensive profile could be developed. The Google/Doubleclick DART cookie is one example where some of these things take place. The information can be used to assist consumers to link up advertisers with the needs of the consumer. The information could also be used against a person, such as part of a civil lawsuit or in a criminal prosecution.