So you may have heard about this game called World of Warcraft. It's pretty popular, clocking in at 4.5 million subscribers and counting. When it launched in November last year, the "experts" had determined, after cashing their consultation fees, that the massively multiplayer market was virtually saturated -- that pretty much everyone who was interested in MMOs was already playing one. Well, one year later, it turns out that those people are rather wrong, and Blizzard Entertainment is hard at work on Burning Crusade, the expansion to their blockbuster foray into the persistent online market.