What is a cookie?

Some Web sites use a small file, called a cookie, to keep track of you and your preferences during your visit. The server that hosts the Web site sends a cookie to your browser. Your browser then stores the cookie in a "cookies.txt" file on your computer hard disk. When your browser requests a page from the Web site, the cookie is sent back to the server. A shopping site might use a cookie to keep track of your shopping cart or your site-specific username and password.

Usually cookies are completely harmless; for instance, your computer can't get a virus from one. A cookie does not grab your name, address, or anything else from your computer. If you choose to enter your name and email address when you visit a site, then a cookie will allow the people who manage the site to keep track of the information you've entered. But it doesn't send any more information than you choose to give out.