Facebook has excellent granular privacy controls.But here's the thing…What's the deal with Facebook's Security Questions???Mother's birthday? — Father's middle name? — Third grade teacher?Security challenge questions based on social information is probably not the best of ideas on a social networking site. Particularly now that Facebook's user base is as expansive as it is.After all, who's going to know personal details about yourself?That's right — your friends.Facebook should revise this sooner than later.