Blizzard's latest expansion for World of Warcraft, Mists of Pandaria, sold 2.7 million copies in its first week on store shelves. On the surface, this sounds great, but in comparison to previous expansions, it hasn't done nearly as well. Wrath of the Lich King sold 2.8 million in its first week, and Cataclysm sold 3.3 million during its first week on sale.
At the same time, since Mists of Pandaria released on September 25th, WoW subscribers have jumped another 1 million. WoW subscribers have been on the decline for some time, and it was down to 9.1 million subscribers in early September. Since the panda expansion pack, WoW has over 10 million subscribers once again.
The numbers sound quite a bit contradictory, but one thing that the 2.7 million number does not include are the downloaded copies sold; it's only what has sold in stores. It's quite possible that Mists of Pandaria has surpassed its predecessors in terms of sales, which would explain the spike in subscribers. Either way, Blizzard probably isn't sweating it that much as long as their subscriber base continues to climb.