Troll: *logs into the chatroom* What happened to us Sarah? Why'd you break up with me?
Sarah: ...I never had a boyfriend...
Troll: Oh, so now you're playing dumb!
Although most people don't know this, it can actually be a good thing to have a troll on your site, since that means it got so popular people want to deface it.
Trolling has also started a few other memes, such as the infamous "Troll Face", which people belive is what trolls look like, and "Troll Dad", some comics ending with a humorous punchline about the dad insulting his son.
Underground Trolling forces made a classic Soviet Song into Trolololololo.. and the rest is history