(1) Posts inflammatory comments, not to engage in serious conversation, but to "grief" or annoy an online community.
(2) An obvious glee and elated satisfaction is aroused in them when people join the fight and reply to their deliberately disruptive comments.
(3) Copies and pastes large blocks of text to exhaust the readers of a topic thread, thus driving away legitimate posters of sincere comments. These blocks of text are often recycled and appeared on a variety of threads.
(4) Tends to avoid complimenting people who disagree with them, even when those in opposition to the troll make some valid points.
(5) Shuns any conciliatory statements like "You have obviously spent a lot of time studying this subject, and I'm not certain how to reply to your last remark, so let's shake hands, part as friends, and move on."
(6) Never ends a debate with "Thanks for the discussion" or "I'll consider what you say" or any other finalizing remark, because they love arguing and disrupting civilized conversations.
(7) Keeps an argument going a lot longer than a normal person would, to the point where people will start asking a moderator to turn off comments or block the troll. However, sometimes people will do this just because they can't tolerate contrary opinions and are angry at seeing them posted to a thread they enjoyed reading. The mark of a troll is to keep hammering away at a point in an obsessive manner.
8) Acts innocent when called a troll, and states "I'm just stating a contrary opinion, and you can't handle it", but the reality is they are not innocent, they are trouble-makers who only post inflammatory remarks, rarely contributing any real value or good information to a discussion.
(9) Starts saying filthy words and making wild accusations when confronted. Their hostility and provoking rhetoric escalates when you ask them if they might be a troll or if they are simply trying to stir up trouble.
(10) When you mention the name of another well-known forum, Second Life, or blogospheric troll, they defend them and accuse you of not understanding that person because you're a tyrannical censoring fascist or whatever.
(11) Will try to bring up issues that they are angry about, no matter what the topic of a thread is. For example, they will say things like "sounds like the Open Source movement" or "reminds me of Tea Baggers" or "you're sounding like a typical commie libtard now" or "you sound like some irrational Creationism crank" or "you atheists are all the same", or whatever it is they're hostile toward, in an attempt to start a new argument within the current debate.
(12) When people realize or are warned that the person is a troll, and the troll is then ignored, and nobody will respond to anything they say, the trolling person tends to give up and go to some other thread. They crave attention and they try to get it by being obnoxious in a juvenile, or scholarly, manner.
(13) They use a nickname, are anonymous, or use a real sounding name, but do not embed a link to their blog or website in their name, as is common in comment forms. This lack of accountability enables them to get away with saying anything they want, to anybody, and even tell outright lies about what they saw or heard.
(14) They, when not confronted or exposed sufficiently, will seek to have the last word in an online discussion. When nobody responds to their last troll comment, they will proudly proclaim that they "won" what they fantasize as a "content" or "battle".