Facebook's ad revenue increased by 69% in 2011

"In its filing, Facebook reported 2011 revenue of $3.71 billion, an 88% increase from the $1.97 billion total reported for 2010, though falling short of eMarketer's 2011 projection of $4.27 billion. The increase was mostly attributed to the 69% growth of advertising revenue, which was buoyed by a 42% increase in the number of ads delivered and an 18% increase in their average price.
While advertising made up $3.15 billion of Facebook's revenues last year, the company earned $557 million from Facebook Payments -- the virtual currency it began requiring game developers on the platform to use as of July 1 -- and other fees. Payments are making up an increasingly hefty chunk of Facebook's revenue, and in the fourth quarter of 2011, advertising constituted just 83% of revenues, down from 90% the previous year. Facebook takes a cut of all money exchanged through the use of "Payments," and in the case of virtual goods purchased on Zynga, that cut is up to 30%."

Source:  AdAge, 1st February 2012