World of Warcraft: Cataclysm has sold more copies in one month than any other PC game - 4.7 million units, according to Blizzard's internal numbers.
This, the third WOW expansion, had previously broken day-one PC sales records by shifting 3.3 million copies.
Mike Morhaime, the man who co-founded Blizzard and probably pays himself a competitive salary, said: "We've been floored by the community's response so far, and we'd like to thank them for their continued passion and support for World of Warcraft, and for helping Cataclysm reach this incredible milestone."
World of Warcraft: Cataclysm ambitiously set out to revamp the entire old world of Azeroth under the guise of returning, destructive super-dragon Deathwing.
Wrote Oli Welsh for Eurogamer: "Cataclysm doesn't just make WOW better. It does something even more valuable than that; it renews it. It fires your excitement at starting on that long road one more time, and invites you to relish the journey just as much as you'll lose yourself in its ending."