An obnoxious user or member on a forum that goes out of their way to make pointless, offensive, or annoying posts and messages. Often these users are labeled as spammers and will post random off-topic junk in many sections of a forum.
User: I think his policies are corrupt and the only reason he remains in office is because of his financial bribes and support requests to other branches of the government. What about you guys?
Forum Troll: I think if you actually had a life, you would turn off your monintor, walk away, and never return to this website again. Of course, it doesn't seem like either will ever happen.
User: I'm going to add a new section to the forum today, so everyone please be patient as I finish this up, and please don't go to the new forum until it's done.
Troll: *goes to new forum* *posts forty new identical topics about his dog*
User: i feel so down today!!!! nothing is workin right for me. my boyfriend dumped me, it's pouring down rain outside, i feel depressed, i have four tests tomorow, i'm a wreck!!!!!! sombody give me sympathy...
Troll: Hey, I've got an idea! Why don't you kill yourself? Then you dont have to be sad, and I dont have to listen to your useless crap! Everybody wins.