Bah! I hate Trolls [http://www.funenparty.nl/pictures/trollzgroep.jpg]! They are the bottom of the filthy scum that teach our daughters to act like sluts!
Wait....oh sorry, wrong troll.
To me, I think a Troll is someone who just posts a comment with no help to anyone that seems like flaming or just nucansing(?). Or maybe they're putting in their opinion without validating why they think that.
An example would be:
Person: I like dolphins!
Person 2: Me to! They are such intruiging mamals!
Troll: Dolphins suck!
Instead of maybe;
Person: I like dolphins!
Person 2: Me to! They are such intruiging mamals!
Not Troll: Ehh, I'm not to fond of dolphins. I much prefer sharks.
Someone could be a troll without knowing it, or more specifically someone could post a trollish comment without meaning to.
But it depends I guess.