In discussing some weird policies in the World of Warcraft online game, Cory Doctorow nicely articulates an important insight about environments like WoW:

Online games are incredibly, deeply moving social software that have hit on a perfect formula for getting players to devote themselves to play: make play into a set of social grooming negotiations. Big chunks of our brains are devoted to figuring out how to socialize with one another — it’s how our primate ancestors enabled the cooperation that turned them into evolutionary winners.

http://www.boingboing.net/2006/01/27/world_of_warcraft_do.html