Here’s an SEC filing for Vivendi, who of course owns Blizzard. I’m a tad busy at work today so I can’t give it the dissection I’d like to, but this number popped out at me:

Over 1,300 Game Masters provide 24×7 customer support in 6 languages directly to players while playing the game.

That’s a whole lot of “I cannot help you with that” – 1 GM per every 5000 paying customers, if my math is correct. That’s a serious commitment to providing and maintaining a high level of quality service.