The actual risk of any given file depends on what sites a person has visited and what level of security those sites maintain. Many companies, such as Yahoo, leave cookies on visitors' computers that allow personalized sites to be recreated at the next visit. Most e-mail and financial sites ask for a separate password before allowing access. Most sophisticated Web sites also encrypt this type of information inside the cookie files, so that any genuinely sensitive data appears as an incomprehensible string of numbers or letters. Not every site takes all of these precautions, however.
Some cookie files show up with unencrypted login names and passwords.
These could potentially then be plugged into such things as finance sites to see if a person has used the same password for both accounts. This aspect is potentially more dangerous for Netscape users, because that program stores all cookies in a single file. IE cookies are also being shared on Gnutella, but the information is stored in multiple files, making it slightly more difficult to cross-reference passwords or other information between different sites. But privacy experts say it would be reasonably easy for someone to write a small, automated script to download cookie files as they were made available or to search individual files for specific information. To guard against this, Gnutella users should make sure they know exactly what folders, directories or drives they are making public, Truelove said.