According to GameSpot, Vivendi Games, the business division of Vivendi to which all the World of Warcraft money goes, made nearly 300 million Euro ($375 million) of revenue (that's not profit) in the first half of 2006. That is a solid 50 million Euro per month. And not all of that revenue comes from World of Warcraft, or even Blizzard. But it is safe to assume that the majority of the cash is coming from there, as the other "solid performer" quoted in the article was Ice Age 2 : The game, and I don't see that one raking in many millions.
So why we still don't know how much money, and especially profit, World of Warcraft is making, we know it is "less than 50 million Euro per month". I already mentioned that people simply calculating 7 million subscribers times $15 tend to forget that the over 4 million Chinese subscribers pay a lot less than the Americans and Europeans. But Vivendi Games is not only making money from monthly fees, World of Warcraft has been in the top 10 PC games sales charts since it came out nearly every week, so even at the reduced price nowadays the box sales add a good bit to the income.
What always surprises me is how relatively little of that money is invested back into the game. It seems obvious to me that Blizzard could easily sell one expansion set per year, SOE has been doing that for years with much less successful games. WoW's first expansion coming out only 2 years after the release is horribly slow by industry standards. And even the free content isn't added any faster than games like Everquest 2 add content. A lot of the unhappyness of the casual players could be mitigated if Blizzard was adding *both* raid content and casual player content, instead of concentrating on the former. With 50 million Euro per month it should be possible to hire a bunch of programmers and do more.