I see two categories of anti-fanboi:
- the Black Hats
- the Competitive Venters
The Black Hats are so-called from the behavior type described by Edward de Bono in his "Six Thinking Hats" model of how people talk about ideas and plans. Basically, the Black Hat kind of person is naturally inclined to see the reasons why an idea is broken, why a plan can't possibly work, and in general all the flaws and dangers of someone else's suggestions.
There's value in Black Hat thinking. It can be useful to highlight the risks and potential costs of doing some thing. But it's not the kind of thinking that should be applied immediately as soon as someone says, "Hey, wouldn't it be cool if...." Applied too early, Black Hat thinking squelches ideas. Even if they really are bad ideas, pretty soon people decide that any idea is going to get hammered into the turf before it can be given fair consideration. And so they stop suggesting ideas.
The easiness of Black Hat thinking (it's always simpler to knock down someone else's ideas than propose ideas of one's own) means that these folks are pretty common on many game forums. Unless they're encouraged by other users to hold their fire, Black Hats can take over.
When that's allowed to happen, the Black Hats usually attract the Competitive Venters. (There's no link for this term; I just invented it. I think.)
The Competitive Venters are the folks who seem to think that "I can pile on more than you can" should be a team sport. They'll wait for a Black Hat to criticize someone's idea, then they'll jump in with their own criticisms, usually of a much more emotional (and less coherent) nature.
It's almost like they're fighting to see who can say the harshest thing. "LOL u r so dumb" is only where this style begins; more sophisticated ad hominem attacks and complaints that the idea's original poster is a fool for not knowing "fact" X or for somehow minimizing the gameplay style that the Venter favors soon follow.
Once the Black Hats and Competitive Venters are allowed to establish their style as the norm in a MMO discussion forum, that forum is pretty much toast as a useful place for discussing the game in question. Often an "in-crowd" will develop that takes a kind of sad pride in crushing any idea expressed by someone who's not part of the established gang. ("Yes, heard that one already -- RTF, n00b!") I've encountered discussion forums whose moderators have allowed this "private sandbox" mentality to take over; they're not fun places to visit.
Fortunately, there are other MMO forums that by policy encourage constructive discussion and tolerance of new and different viewpoints.
These places must be defended. There aren't enough of them.