Learning from failures
Doubleclick
as you learned in chapter 5, Doubleclick is one of the largest banner advertising networks in the world. Doubleclick arranges the placement of banner ads on web sites. Like many other Web sites, Doubleclick uses cookies, which are small text files placed on web client computers, to identify returning visitors.
Most visitors find the privacy fisk posed by cookies to be acceptable. The Web servers at Amazon.com,for example,place Amazon.com cookies on the computers of visitors to the site so the visitrs can be recognized when they return. this can be useful,for example, when a visitor who has placed several items in a shopping cart intact. The amazon.com web server can read the client's Amazon.com cookie and find the shopping cart from the client's previous session. The Amazon.com server can read only its own cookies; it cannot read the cookies placed on the clicnet computer by any other web server.