Care2.com user Jonathan B. was kind enough to provide me with this definition of an internet troll. This one is specifically geared towards those trolls who engage in so-called 9/11 debunking...
Internet poster who takes oppositional views to any advocacy site, regardless of the actual strength of his chosen position, for the pure purpose of stirring up debates, generating anonymously, and triggering hatred.
Goal of Trolling- The feelings of superiority and laughs that come from generating hatred, bad feeling, or confusion on the target of trolling, and attention generated from getting targets to respond.
Tools of Trolling-
1. Ad hominem insults of posters mental status, looks, intellect, or typing skills.
2. Disregard of any fact that does not back the troll's advocacy position, and excessive focus of any debunker information, regardless of the motives of the debunker.
3. Endless verbosity when arguing any position, regardless of logic or reasoning or actual facts, but a lot of use of "facts" discussed generally, but never quoted or sourced. Example- Thousands of scientists say I am right.
Payoff of trolling-
1. Making other people feel bad, without the risk of getting one's face punched in, for being rude, cruel, or socially uncaring.
2. Bullying without the mess and fuss and muss of actually answering for bad behavior.