Blizzard has revealed that the company’s recently released World of Warcraft: Cataclysm has become “the fastest-selling PC game of all time” after selling over 3 million units in just 24 hours of availability.

Based on “internal records,” as well as “reports from key distribution partners,” 3.3 million copies of the third World of Warcraft expansion were sold in only one day, both at retail and through digital distribution, including pre-sales.

The previous PC game sales record-holder, Blizzard’s own World of Warcraft: Wrath of the Lich King, sold ‘only’ 2.8 million units in 24 hours when it launched at the end of 2008 – Cataclysm has clearly eclipsed this record.

Currently, 12 million players are subscribed to World of Warcraft, Blizzard’s industry-crushing massively multiplayer online RPG.

This past week, following the release of Cataclysm on December 9th, the game ‘only’ achieved a No. 3 ranking on Chart Track’s UK software sales chart, and was outpaced by Call of Duty: Black Ops and FIFA 11, almost certainly as a result of the game’s digital sales eating into retail sales.