Honestly, the only way to really defeat them, assuming that is one's aim, is to IGNORE them.....because, at the end of the day, they are all about the attention, and the reaction, and sans that, they go away. Now believe me, & nobody knows this better than me, but ignoring them is easier said than done.....and quite frankly, having a go at them every once and awhile is more fun. However, even when having a go at them, doing it rationally & not actually "losing it," in a way, defeats them, at least slightly.
Sadly, just as it only takes one rotten apple to ruin the bushel, it only takes a few "trolls" (truly miserable people really) to ruin the atmosphere in a forum such as this. Remember, in my opinion anyway, a troll can actually be an active poster...so long as his intent is to basically bait, goad, incite, and basically start something &/or cause trouble at every turn. I'm sure we would all agree that there is more than one person on this forum that fits that definition to a T! It just makes one wonder what could happen to make someone that miserable that they find the need to share their special brand of misery with the world in an effort to make others miserable too...but thats a discussion for another place & time! Ha ha ha!
But, as I said, the ONLY way to REALLY defeat them is by not feeding them, and the ONLY way to do that is by IGNORING them! :2 cents: