Diablo 3 launched back in May, with 3.5 million snatching the game up within the first 24 hours. In North America, NPD stated that Diablo 3 sold one million retail copies across May. The current version of the game, 1.0.5, has been available since October 25.
Update: An expansion for the game is also in the works, Blizzard Entertainment president Mike Morhaime announced during the call: "We do have an expansion planned for Diablo , I don't have any timeline to talk about. I think the most important thing for us always comes down to the quality of the expansion and the gameplay, so that will be a big factor in terms of driving our schedule."