Armin Weigel, DPA / Corbis
Logged in or not, Facebook tracks you across the Web. The company went into detail about its procedure for tracking users, explaining that when someone visits a Facebook.com site—even if they don't have an account—the company puts a cookie on their browser that records the date, time, and address of every site they visit that has a Facebook “like” button or plug-in. In addition to which websites you visit when, the cookie records unique characteristics of your computer, like your IP address and operating system. If you're logged into your Facebook account, the company puts a second cookie on your computer that records your name, email address, friends, and other information. Facebook says it uses the data only to improve usability and security, and that the information is deleted after 90 days.