Useful Facebook Hack

When you log into Facebook on your friend's devices or a public computer, it's easy to forget to log out again. "Security Settings" tells you where you're logged in, when you logged in, and gives you the ability to "End activity," so no one can hack your profile. Go to "Settings" and then scroll down the left column to "Security." Click on "Where You're Logged In" and then end activity on ~mysterious~ devices.