Another good one posted by a Facebook friend:
I would say I'm the Gamer.
They missed one type of Facebook friend. I have people that never post anything personal but post a lot of news articles, funny pictures, etc. Maybe you could call them the Journalist or the Viral Spreader (meaning they're doing their part to make something cool or noteworthy go viral)?
I don't see the difference between the Hater and the Cynic. Sounds like the same creature to me.
I just thought of another type, sort of the opposite of the Hater. They love everything and everybody and are always posting mushy stuff, cutesy stuff, or responding to everyone's posts with cheery messages. Kind of the Sunshine and Lollipops personality, or Mr./Ms. Feelgood. They're so effusive it makes you doubt their sincerity or you wonder if they're really grounded in reality.