illustrates how these systems work. Advertising networks begin with a
consumer requesting a page from a member of the advertising network (1)
. A connection is established with the third-party ad server (2).
The ad server identifies the user by reading the cookie file on the user’s hard drive and checks its user profile database for the user’s profile (3).
The ad server selects an appropriate banner ad based on the
user’s previous purchases, interests, demographics, or other data in the profile (4).
Whenever the user later goes online and visits any of the network member sites, the
ad server recognizes the user and serves up the same or different ads regardless of
the site content. The advertising network follows users from site to site through the
use of Web tracking files (5).