Fanboy via Flame Warriors by Mike Reed

Though annoying and often disruptive, Fanboy is
a relatively harmless Warrior because his interests and knowledge are
strictly limited a single obsession. He's fixated on a particular video
game, a celebrity, a television show, a sports team, – almost anything,
really. Fanboy’s compulsion makes him very easy to identify, but
it also arms him with supernatural tenacity. The most benign criticism
of his beloved immediately provokes a cascade of virulent abuse. Once
alerted to Fanboy's sensitivities Evil Clown, Troller and Jerk will
goad himmercilessly.

CAUTION: ANYONE can become a Fanboy, but the warning
signs of an emerging Fanboy are subtle and easily overlooked. For example,
are you a little hasty to defend Linux?

[Fanboy]