2) Irrating others who have a different philosophy/viewpoint than theirs
3) Trying to invalidate what the other folks on the forum believe in.
For example, a troll could be someone who is super gung-ho primal and posts a bunch of stuff on vegan forums about how everything they do and think is wrong, etc...or a vegan posting a bunch of studies on this site about how red meat causes heart attacks.
Trolls have no interest in actually debating a topic, they mainly just want to piss people off and often revert to using cheap tactics to sidestep having to answer any legitimate questions.
You don't seem to understand what a troll is:
A troll is somebody that deliberately posts things that others will find offensive or have a negative emotional response to. Making a satirical/joke post is not trolling, insulting somebody is not trolling, posting a dissenting opinion is not trolling, and as a troll, you do not have believe the things you say. Thus arguing with a troll is the wrong thing to do, you are validating their posts and playing their game.
Ignoring trolls the only solution.
Curiously, unlike the D&D trolls, the on-line trolls are not killed by flames and acid, but feast and regenerate on it.
My Journal: http://www.marksdailyapple.com/forum/thread57916.html
When I let go of what I am, I become what I might be.