Activision today announced that Infinity Ward's blockbuster military shooter, Call of Duty: Modern Warfare 2, has accumulated over $1 billion in estimated global retail sales. The title's popularity has far exceeded expectations, shattering numerous entertainment records, and even becoming the most pirated game of 2009, despite its late-year release.

"There are only a handful of entertainment properties that have ever reached the $1 billion mark, which illustrates the power of the Call of Duty franchise and the mass appeal of this game," said Activision Blizzard CEO Robert Kotick. Modern Warfare 2 generated $550 million sales during the first five days available, surpassing box-office hits like Harry Potter and the Half-Blood Prince, as well as games such as GTA IV.

Naturally, the game has been popular among pirates too, and the PC version of MW2 alone pulled in some 4.1 million unauthorized downloads in less than two months, compared to The Sims 3's 3.2 million downloads in a six-month period.

As for the future? Several downloadable content packs are due this spring, and rumors suggest that Infinity Ward's next project will be an MMO while another developer might pick up the Call of Duty franchise.