It's usually when someone -like a friend or family member uses anothers computer while their facebook account is logged in and dishes out flattering comments about themselves, purporting to be from the original user.
My kids have attacked mine occasionally with self appraising comments..and also announced to the world-- (well the 30 or 40 friends & family I have on there anyway) that I've decided to come out of the closet and rejoice in the fact I'm actually Gay.....which so happens I'm not.........(not that there's anything wrong with that..)