This is Internet On The Air. I'm Joan Silvi. A cookie you can't eat...and you'd probably rather not have in your hard drive. Details in a moment.

Funding Credit: Internet On The Air is a production of the University of Michigan School of Information and Michigan radio, made possible by a grant from the W.K. Kellogg Foundation.

Persistent client state HTTP cookies. That's a mouthful that has nothing to do with cookies that you'd buy at a store. These cookies are data shortcuts that may be entered in your hard drive without your permission...or even without your knowledge.

When you access a Web page, the server can ask for your user information, and then ask to store this information in your hard drive. When you return to that Web page, the server calls up the cookie, reads it, updates it and stores the new information in your hard drive again.

Usually, this information lists your preferences so the Web page can be "customized" for you. Web page designers also use information retrieved from cookies to change and improve their site. But there are concerns about privacy. Cookies can amount to an invasion of privacy, because they can identify you and track your visit. When you've been tracked by a cookie, you're no longer an anonymous browser. Designers - and maybe others - know who you are...and what you're looking for.

The good news is that some Internet search tools, like Netscape and Microsoft Explorer, have installed applications that can notify you when a cookie is trying to enter your hard drive. You can refuse the cookie, but still visit the Web site.

For more information on Persistent Client State HTTP cookies, visit our Web site at www.si.umich.edu/iota. For Internet On The Air, I'm Joan Silvi.