Fergie's Tech Blog

Computer Cookies and How They Crumble

Alex Mindlin writes in The New York Times:

Tiny files called “cookies” are the lifeblood of online advertising. When a computer visits a site or sees an ad for the first time, the site’s server slips a cookie onto the visitor’s hard drive, identifying the computer in future dealings with that site or ad network. Cookies let online hosts determine the number of unique visitors they reach, a key metric for advertisers.

But this system of measurement has a well-known flaw: users are prone to delete their cookies, either manually or by using antispyware programs. Users who delete a cookie are eventually given a new one by that cookie’s issuer, meaning that they are often counted as unique visitors, inflating the numbers at host sites.

posted by Fergie @ 6/18/2007 07:22:00 AM