OSD revenue increased primarily as a result of growth in online advertising revenue. Online advertising revenue grew $81 million or 13% to $713 million, reflecting continued growth in search and display advertising revenue, offset in part by decreased third party display advertising revenue. As of December 31, 2011, according to third-party sources, Bing organic U.S. market share grew over 25% from December 31, 2010 to approximately 15%. Bing-powered U.S. market share, including Yahoo! properties, grew over 9% during this same period to approximately 27%.
OSD operating loss decreased due primarily to higher revenue and lower sales and marketing expenses, offset in part by increased cost of revenue.