The Troll, or Terrorist Rampaging On-Line Looser, is basically an attention whore and someone who does things to call attention to themselves.  It is a bad thing if the troll is stupid or just trying to bring attention to himself/herself or just out to annoy people.
Let's start by getting our definitions straight: An Internet troll is someone who comes into a discussion and posts comments designed to upset or disrupt the conversation. Often, in fact, it seems like there is no real purpose behind their comments except to upset everyone else involved. Trolls will lie, exaggerate, and offend to get a response. 
Trolls are a breed of creatures who like to post inflammatory, extraneous, or off-topic things on the Internet that are often very provocative and misleading and can cause emotional distress. The average Troll can often be found wielding a club and a laptop Computer for on-the-go trolling. Contrary to popular belief, trolls are rarely young children and are usually either teens or adults with no social life.
The worst trolls, those who admit trolling is their favourite Internet activity are Machiavellian, Narcissistic, borderline Psychopaths or worse, and sadists. If you can ignore them that's usually best.  I know the worst trolls are bad people. I know the very bad stuff I sometimes have to delete here.
Note: Golbeck only referred to the worst trolls. Teens who go through a phase when they do a bit of trolling and a great deal of other online stuff shouldn't worry that they may be very bad people. Trolling without a very good reason isn't nice but it doesn't make you a horrible person unless you do it all the time and/or do it in very bad ways. Teens or adults who get tempted to troll after reading bad stuff at Conservapedia, after Andrew Schlafly and/or other Conservapedia Sysops have messed with them, may not be bad people at all.
Sometimes trolls are very funny as well as annoying. While they get a rise out of people most in the troll culture learn to spot their own kind and sometimes have troll battles, and indeed if one trolls better than the other there is an acknowledgment of "better troll" which usually means funnier.
Reverse trolls are the sort of intellectual type trying to get people to pay attention to what they are saying cause they aren't ego maniacs just like to talk about what they want to talk about.
With the advent of the political blogosphere the troll is seen as someone who politically differs from the main purpose of a blog or wiki, for example if someone came here and said something like "George Bush rules! He was the best president ever!"- , this would be evidence of troll-like behaviour.
- ↑ Online argumentativeness isn't necessarily a bad thing if the argumentative person is intelligent and is trying to bring attention to certain issues but true trolling is just done to annoy other people.
- ↑ 2.0 2.1 Internet Trolls Are Narcissists, Psychopaths, and Sadists