I'd just like to point out that a common attack vector is password reuse. If you use the same password all over then internet, then if any server you have an account with is hacked, it's fairly likely they will be able snag all the passwords, find yours, and hack your Facebook account.
Realistically, I find it hard to believe that an uber hacker would bother with posting obnoxious messages to your FB. That sounds personal to me.