Someone who's only intention when posting to or commenting on Facebook is to stir the shit.
Posts supporting something a majority of people can't stand. Comments intended to piss off the original poster and/or start a series of argumentative comments.
Posts such as:
Obama is as big of a hypocrite as Jesus.
If I have to pay for healthcare I'm not going to be able to buy my 5 kids each new iPads.
The (sports team) is worse than my 5-year old's team
You should reply to all of these with "shut up you Facebook toilet"