A person who spends hours on the internet(mostly YouTube) everyday, trying to sway the minds of anonymous people by posting politically or socially based propaganda, because they are incapable of debating in person. In other words: a mentally unstable person, with far too much time on their hands.
" Man I can't stand that guy. He is always trolling the same videos posting the same rhetoric day in, day out."
" Aw, forget about him, he's a fucking keyboard crusader."