There was a news flash about trolling on DR1 today (Translated: Danish Radio 1) about trolling.
Apparently, trolling is the act of gaining information about someone through Facebook, and then hang them out (read: bully) on Facebook, Youtube, Skype or other social networks.
And then they interviewed a "troll" while he was anonymous. He had several times commented on videos of people with signs with stuff written on them about how they had been bullied, and he was doing it because he thought that "people should be able to criticize whatever they want," and stuff like that.
I don't know about the danish news, but that sounds like an extremist cyber-bully.
Trolls do it for the lulz.
At least they got the trollface right.