Who uses it: Participants in Internet forums
What it means: Someone who posts to a forum or leaves a comment on a blog in order to enrage or embarrass other participants.
How you can use it: When someone's being deliberately annoying.
This blog doesn't get many trolls, thank goodness, and neither do the handful of Web forums I visit regularly. Trolls seem to be more common among teenagers and hardcore technology types -- my guess is that they feel powerless in other areas of their lives, so take pleasure in disrupting things anonymously.
I understand that impulse to wreak havoc anonymously. The lady who lives next door to my apartment building, whom I've never met, opened her door yesterday morning to snap at me: "Please don't let your dog pee on my trees." I hadn't realized that the trees, a row of cedars between her property and my building, belonged to her; nor had I thought that Dizzy could do any harm to the trees by watering them. Nevertheless, I apologized profusely, and said it wouldn't happen again.
Then, as I took Dizzy down to the river, I thought about getting up in the middle of the night to pour something really caustic onto the trees, something like bleach or drain cleaner; I'd do it the night before leaving town for a while, and when I'd come back, all the trees would be dead, and she'd never be able to prove I did it. Ha ha!
And then, of course, my brain returned to its regularly-scheduled programming. The trees are nice, and it's not their fault that they belong to a cranky old lady. I might even mulch them, just to show my neighbor how sincerely sorry I am for annoying her. (Because I am; I feel terrible about it, like a kid who behaved badly.)
Revenge fantasies are fun, but the difference between normal human beings and sociopaths is that normal human beings enjoy the fantasy, then let it go. Trolling on Internet forums isn't quite as destructive as pouring bleach on trees, so maybe we should be glad that they're online and not letting the air out of people's tires.