Somebody who finds refuge from the sheer mundanity of everyday life in the bosom of a particularly engrossing videogame. General stereotypes have already been mentioned, but in my experience with fellow gamers, they are largely misanthropic and just find most people uninteresting. This could perhaps explain why many are seen as socially inept and introverted, but then again, I doubt misanthropia is a popular mindset. The gamers I know are well-read and erudite (in contrast with the idea that games 'rot your brain' - ever noticed how people who make such claims are usually Big Brother watching idiots themselves?).
A very, very stupid word used to try and rob 'fans' of something of their credibility and validity. Usually used in the video gaming world, and employed by those who could be described as 'fanboys' themselves.
The word totally fails as an insult, and serves only to make the attacker seem incredibly childish. It also fails in that nobody is ashamed to call themselves a 'fan' of something - are they?