An important fact to keep in mind is that Facebook isn’t monetizing these impressions at the same rate as its rivals, and that these stats demonstrate Facebook’s dominance only as a publisher. Microsoft and Yahoo serve ads on other sites through their ad networks — and, in fact, Microsoft delivers most of the ads that appear on Facebook. But this is a huge milestone for Facebook, and helps solidify its position as the largest destination on the Web. And Facebook’s ascent could help fuel the online advertising market, which shrank during the recession — as budgets have returned, display ads have recently rebounded strongly.
Facebook’s ad growth also reflects increased demand from both large and small advertisers, says comScore Chief Marketing Officer Linda Abraham. It “remains to be seen” whether its growth is coming at the expense of rivals, she said. “The data has to play out over the next couple of months to definitely say that.”