Facebook Earned More Than $3B in Ad Rev in 2011

"Facebook's 2011 advertising revenues were $3.1 billion, up 69 percent from the year before, according to the Menlo Park, CA-based firm's S-1 filing today for its initial public offering. Facebook, which has increased its ad units per page from four to seven in the last two years, appears to have benefited greatly from those particular moves," notes ClickZ. "According to the filing, the primary reason for the jump in ad revenue was a 42 percent lift in the number of ads delivered, as well as an 18 percent hike in the average price per ad delivered." Read more.