How do people hack into Facebook accounts?

[Anna]

My account has been hacked in a few times and AD's posted to my feed/status. No one knows my password and I don't write it down or use it for anything else? How does this happen?

[JayeeGOthoee]

hackers duh ! there conniving little losers with no personal ambitions except to ruin or gain access to other peoples personal things and information ! change your password frequently , it helps !

[Shoâ„¢]

It's a technique called brute force hacking. The problem is you don't have a strong enough password or brute force would not work, by a strong password I mean Ru678Nk100UhF<---that password is virtually uncrackable.

I know it's a pain because you would have to write such a password down somewhere but it would also ensure that they can't hack into your FB.