IRVINE, Calif. – December 19, 2005 – Blizzard Entertainment, Inc. today announced that World of Warcraft®, its massively multiplayer online role-playing game (MMORPG), has surpassed five million customers worldwide. The subscription-based MMORPG launched approximately one year ago in North America, Australia, and New Zealand and has since released in multiple countries throughout Europe and Asia.

So then... 5 million people paying roughly $12 - $15 per month would be $60 - $75 million each month. Perhaps if they work really hard they get to gross over a billion dollars next year.