Trolls and other monsters
I just posted this to the Rumor Mill, but I'd meant to post it here a couple days ago:
To "troll," in an online discussion forum, is to post something that's not meant seriously, but is intended to provoke outraged response from regulars. Canonical example: posting to a Star Trek discussion forum stating firmly that the "T." in "James T. Kirk" stands for "Tigger" ("I heard it from Jean Roddinbury herself!") when you know it's not true—you're doing it just to be amused at people's "How could anyone be so stupid/clueless!?" responses.
A message that doesn't have the intent to provoke outraged response isn't, technically speaking, trolling.
Note that the term comes from fishing, not from fantasy novels. The person who's trolling—the "troll," in net parlance, though not in fishing parlance—is fishing for a certain kind of response.