Online advertising revenue grew $109 million or 15% to $823 million, reflecting continued growth in search advertising revenue, offset in part by decreased display advertising revenue. Search revenue grew, primarily due to increased revenue per search. According to third-party sources, Bing organic U.S. market share for the month of December 2012 was approximately 16%, and grew 120 basis points year over year. Bing-powered U.S. market share, including Yahoo! properties, was approximately 26% for the month of December 2012, down 90 basis points year over year.
OSD’s operating loss was reduced by higher revenue and lower cost of revenue and sales and marketing expenses. Cost of revenue decreased $72 million, driven by lower traffic acquisition costs and Yahoo! reimbursement costs. Sales and marketing expenses decreased $31 million or 16%, due mainly to decreased advertising and corporate marketing activities.