There's a new FaceBook virus going around. It's actually a "Phish", which means you are baited into going to a false page that looks just like the FaceBook login page, where unsuspecting people may think they've somehow been logged out of FaceBook and re-enter their login and password. Once they do, the "phishermen" log and save your login information, and use your profile however they want.
This one starts in the form of a FaceBook App / Game notice, or a shared news item / link. Once infected, your account will start sending out mass notices to get more people to hopefully enter their login credentials on the fake login page.this info is available on Geekdrop.com