Blizzard has declared World of Warcraft: Cataclysm to be the fastest selling PC game of all time. According to the company’s internal data, the newly released expansion for its monolithic MMO sold 3.2 million copies within the first 24 hours of its release on December 7th. This achievement dwarfs the former record of 2.8 million copies set by Blizzard’s previous World of Warcraft expansion, Wrath of the Lich King, released in November 2008… …