Facebook is dominating the U.S. display ad market, according to data from comScore.
In Q3 2010, Facebook served 297 billion display ad impressions giving it 23% of the U.S. market for display ads. In the first quarter of 2009, it only had a 7% share.
Yahoo came in a distant second place for Q3 2010 with 141 billion display ads and 11% of the market.
As you can see in the chart below, Facebook’s share of the display market has that “hockey-stick” growth, which should be scaring Yahoo, Google, and AOL.