Valve announces that Left 4 Dead 2 has sold over two million copies in the two weeks the zombie shooter has been available, also mentioning that DLC plans for the game will be revealed soon:

Released just two weeks ago, over 2 million retails copies of L4D2 have been sold worldwide and the game appears to be on target to become one of the top selling Xbox and PC titles for the month of November. Sales to date are more than double the original title, which was released exactly one year prior to L4D2. And "Black Friday" promotions during the title's second week of availability in North American resulted in stronger than expected sales in L4D2's bid to become one of this year's best selling releases on both platforms.

"Left 4 Dead 2 is off to a great start with strong support at retail and great reviews from the press," said Doug Lombardi, VP of marketing at Valve. "Meanwhile the title has already been played by over 1 million Xbox LIVE Gold account holders, and news regarding L4D2 DLC 1 is coming very soon."