Facebook accounts for one quarter of display ads in U.S.

In the United States, Facebook accounted for 25.8 percent of all display ad impressions in the last quarter of 2010, up from 23.1 percent in the previous quarter, according to comScore.  

Yahoo! lost some of its display ad share, dropping to 9.7 percent from 11 percent, while Fox Interactive Media dropped from 3.8 percent to 2.4 percent, MediaPost reported. Microsoft's share decreased to 4.5 percent from 5 percent, and Google slipped from 2.7 percent to 2.4 percent. 

AOL reported a small gain on display ad share from 2.4 percent to 2.5 percent in the fourth quarter. 

Total ad impressions reached more than 1.3 trillion in the quarter, about the same as the prior quarter. This means Facebook was responsible for 338.6 billion, MediaPost pointed out. 

The new data shows that Facebook is dominating display advertising based on its audience base of more than 500 million worldwide, as well as its high user engagement. According to Nielsen, a U.S. user spent six hours and 35 minutes on Facebook in March 2011, compared to 2:26 for AOL, 2:16 for Yahoo, 1:26 for MSN/Windows Live/Bing, and 1:21 for Google. 

Facebook surpassed Yahoo last year in ads served and became the leading display ad publisher in the U.S. According to an eMarketer report released in March, Facebook is also expected to overtake Yahoo in display ad revenues, and its overall ad sales are forecast to reach US$4 billion in 2011.