If you know anything about the Internet, apart from it not being a dump truck but a series of tubes, then it is that you shouldn't feed the trolls.
Simply put an Internet troll is just a jerk who posts things on Internet fora and pisses everyone off.
Now we are told to not feed these guys, but we can't help it can we?
People find it fun to bait the troll and it does increase the trollness of the place because it pisses other people off as well.
But it is fun though, watching the troll run around in little circles yelling:
"OMFG BUSH IS A FAGOT !!!1!1!oneONEone1"
And other stupid things in 'leet-speak' that is completely incomprehensible to a normal person of the Internet.
Although there is one downside. And that is if the troll brings friends. Then it can get really annoying.
You do get sick of the 9/11 threads or the evolution ones, and you get rather quick on the attack.
However some people who you might think is a troll is probably just some guy who wants to have a proper discussion but has a stupid viewpoint.
The trolls are the ones that don't change.