Valve looks to be on track to set a record with the largest number of pre-orders of any product in company history. The strength of the pre-orders for Left 4 Dead 2 is perhaps a surprise to Valve, as they have only a little over 3 million units of the first installment of the franchise.

The company is set to ramp up its advertising, as the company will invest $25 million in an ad campaign to get the word out for Left 4 Dead 2 in an effort to push sales even higher. The investment of $25 million in advertising is the largest ad campaign that the company has ever embarked upon, and far larger than the $10 million that the company invested in advertising for the first Left 4 Dead title.

Set to arrive November 17th   for both the Xbox 360 and PC platforms, it will prove interesting to see whether or not all of the advertising dollars spent equal more sales of Left 4 Dead 2.