Facebook's 1.3 trillion display ad impressions accounted for 27.9 percent of all the display ads served online in 2011, according to comScore. The biggest content-related companies were Yahoo (#2 at 529 billion impressions) and AOL (#5 at 131 billion). These companies' dominance of display ads is likely helped by their ability to target ads to relevant visitors. Pew Research Center recently found Yahoo targets more ads (67 percent) than other news sites. Facebook personalizes almost all of its ads based on a user's demographics, interests and friends. News orgsĀ mostly do not target ads. || Related: comScore also reports Web users spend about 5 percent of time on news/information sites, and 17 percent on social networks. || Earlier: Online advertising passing by news organizations (Poynter)