1a. Noun One who posts a deliberately provocative message to a newsgroup or message board with the intention of causing maximum disruption and argument.
1b. Noun A person who, on a message forum of some type, attacks and flames other members of the forum for any of a number of reasons such as rank, previous
disagreements, sex, status, ect. A troll usually flames threads without staying on topic, unlike a "Flamer" who flames a thread because he/she disagrees with the content of the thread.
1c. Noun A member of an internet forum who continually harangues and harasses others. Someone with nothing worthwhile to add to a certain conversation, but rather
continually threadjacks or changes the subject, as well as thinks every member of the forum is talking about them and only them. Trolls often go by
multiple names to circumvent getting banned.
I'm not saying I'm just saying... This ends today's Urban Dictionary lesson Guido