Yes, in a twist that surely suprises no-one, Blizzard announces that WoW now has over 8,000,000 subscribers worldwide. This includes 2 million in North America, 1.5 million in Europe, and 3.5 million in China. They have a fairly tight definition of "subscriber," too: a subscriber is someone with active paid time or game card time, people within their free month, and "Internet Game Room players who have accessed the game over the last thirty days" (not really sure what that last one means). They don't count people with trial accounts or lapsed subscriptions.
Come to think of it, that 2 million in North American actually feels low to me. If you add up the populations of the US and Canada and divide by 2 million, you get 167: one in every 167 US/Canada residents is a WoW player, approximately. It feels like more than that to me, but that probably says much more about the kind of people I know than anything else.
I can't help but think back to when I first heard about WoW, when Blizzard announced it as their next project. I was upset, since I figured I would never want to play a game that required a subscription fee (I was a huge Diablo II fan at the time), and like everyone else, I underestimated the size of the MMO market in general. Which just goes to show, when Blizzard announces that their next project is a cross between NiGHTS Into Dreams, Cooking Mama and DDR, don't doubt them. They'll find a way to pull it off.