The term is also thrown onto targeted harassment of random people who make themselves vulnerable in some way, either by real or perceived transgressions. Remember that lady who posted "hope I don't get AIDS, oh wait I can't I'm white" which is absolutely a self-effacing bit making fun of racist white people, not making fun of brown people.

But on the surface it kind of sounds racist, so a bunch of couch potato freaks realized they had the power to just psychotically destroy someone's life for sport, and she was fired before she even got back on twitter and saw the kajillion replies.

That's another one that needs its own name - all these separate concepts need their own differentiators.