Or explained by GamePro: The Psychology of Fanboys|
My favourite bit of this was learning that the author of the excellently titled "Primal Branding: Create Zealots for Your Company, Your Brand, and Your Future" worked with Bungie on Halo's advertising campaigns. *chuckle*
In Primal Branding, Hanlon describes his theory on why consumers become so attached to certain brands while remaining apathetic to others, even if they're similar. He describes them as the creation of a belief system and gives seven characteristics of these strong brands: origin story, creed, icons, rituals, pagans (or "nonbelievers"), sacred words, and a leader. In essence, it's the formula for making people feel as though they are part of a team when they purchase a product, and it's not hard to see this lists' relation to the most popular gaming corporations.
Anyway, some deep thought on a much maligned subject. Worth a read.