2011 Compared to 2010. Revenue in 2011 increased $1,737 million, or 88% compared to 2010. The increase was due primarily to a 69% increase in advertising revenue to $3,154 million. Advertising revenue grew due to a 42% increase in thenumber of ads delivered and an 18% increase in the average price per ad delivered. The increase in ads delivered was driven primarily by user growth. The number of ads delivered was also affected by many other factors including product changes that significantly increased the number of ads on many Facebook pages beginning in the fourth quarter of 2010, partially offset byan increase in usage of our mobile products, where we do not show ads, and by various product changes implemented in 2011that in aggregate modestly reduced the number of ads on certain pages. The increase in average price per ad delivered was affected by factors including improvements in our ability to deliver more relevant ads to users and product changes that contributed to higher user interaction with the ads by increasing their relative prominence.