You Want Cookies On Your Computer?

Q: I keep hearing that some Web sites leave "cookies" on the hard drive of a personal computer. What are they, and should I allow my PC to accept them?

A: A "cookie" is a small file that a Web site deposits on your hard disk, often with a unique number that identifies you. The next time you go back to that site, the computer will know it's you.

Cookies can make browsing more convenient by allowing sites to "remember" how you like to view pages, what sorts of things you like to look at, and so on. If it's a site that requires a user name and password, accepting a cookie can allow the site to remember who you are so you don't have to log in every time you visit.

Despite the conveniences they offer, cookies have raised concerns among advocates for electronic privacy who say they can be used to track personal information and preferences about Web surfers, such as which other sites they visit.

"People feel that on the Internet they're fairly anonymous, but cookies are one of the ways that are whittling down that anonymity," says Ethan Preston, a legal researcher for the Electronic Privacy Information Center in Washington, D.C.

To see what kind of cookies your browser has accepted, do a search for files containing the word "cookie." You should find a set of files from different Web pages with some numbers in them.

Jason Catlett, founder and president of Junkbusters Corp., a privacy advocacy group in Green Brook, N.J., says it's nearly impossible to tell just from the cookie what kind of information the Web site has stored about you, since often times all the cookie contains is a set of numbers used to identify you, kind of like a bar code.

But Catlett cautions that online advertising firms can build up profiles of Web users by tracking what kind of sites they visit and sending the information back to the advertising firm's computer.

"Cookies can be used to customize sites, but they can also be used for surveillance," he says, opening the way for marketers to target you based on information gleaned from your online profile.

You can slow down the intrusion of cookies by instructing your browser to only accept cookies that are sent back to the originating site, and not forwarded to a third party. You also can block cookies entirely, but you may find it inconvenient to remember all those passwords for Web sites.

You can usually change these settings under your browser's "preferences" menu. For more help, look at Junkbuster's Web site, www.junkbusters.com.

Finally, in case you were wondering, the term "cookie" comes from computer science terminology and was not cooked up in a marketing lab, Catlett says.