PC World - The modern military shooter that's sold an astonishing 14 million copies worldwide since November 2009 can check off another record-snapper: Fastest selling downloadable content pack. Released just nine days ago, the $15 Modern Warfare 2 map pack, dubbed "Stimulus Package" by Activision and time-exclusive to the Xbox 360, has been downloaded over 2.5 million times, 1 million of those in its first 24 hours of availability.

Source