According to research by ComScore, Facebook’s 1.3 trillion display ad impressions accounted for 27.9% of all the display ads served online in 2011. It was followed by Yahoo, with 529 billion impressions. These companies’ dominance of display ads is likely due to their ability to target ads to relevant visitors.

Pew Research Center recently found that Yahoo targets about 67 % of its ads, while Facebook personalizes almost all of its ads based on a user’s demographics, interests and friends. Meanwhile, most news organizations do not target ads.

Related Story: News publishers struggle with online ads

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