DoubleClick didn t create the ad, but we did place it there. But click-through tracking yields another dividend, too. As DoubleClick quickly discovered after it began marketing the service, click-through technology opens the door to tracking individuals as they move from one site to another. It s no wonder that from the start, privacy advocates objected to such tracking, but DoubleClick and other rms in the online marketing world pressed ahead. To make the tracking work, DoubleClick used cookie les.
Cookies are random number strings like ngerprints that identify one computer to another.
As you visit a page with a DoubleClick ad, the company places a cookie on your computer. After that, DoubleClick can track your movements through its network even if you do not click on its banner ads. And now, with Web bugs, DoubleClick can track you even when there are no banner ads on a page. And if you make a purchase or ll out a questionnaire on a site with a DoubleClick ad, the rm will more than likely collect that information from the Web bug and link it to your cookie. Last year, DoubleClick tried to take the next step, and link its cookie les with actual names and identities.