Cookies can be a force for good or for evil. Unfortunately, the choice is not ours. Netscape introduced its cookie specification with Navigator 2.0. Once you've got it, every time you click on the Web site, your browser throws the cookie right back. Cookies have taken a lot of heat since they were introduced earlier this year.
Cookies make it possible to track a user's movements on the Web.
And since cookies can be persistent, staying on the user's hard disk for months or even years, they make it easy to see how a person's interests or use of a site changes over time - an invaluable tool for marketers, in particular. But what's really unsettling is that everybody's getting into cookies just to track Internet users. Some Internet advertisers, like The Doubleclick Network , use cookies to measure responses to advertisements. Cookies let Doubleclick display a sequence of advertisements to a single user, even if that user is jumping around between different pages on different Web sites. You can target users by area of interest.