• by Gavin O'Malley  @mp_gavin, February 22, 2012

Growing faster than some experts expected, Google’s display advertising business is on pace to surpass Facebook’s by next year, according to eMarketer.

In 2013, eMarketer anticipates that Google’s U.S. display revenues will grow 45.3% to $3.68 billion, while Facebook’s will grow 27.6% to $3.29 billion.

David Hallerman, principal analyst at eMarketer, attributes Google’s astonishing success to a thriving mobile display business, YouTube’s expanding role as a venue for premium display inventory, and strong growth from the company’s DoubleClick ad network.

“The strength of Google’s existing relationships with search advertisers has also been a tremendous help for the company’s display business,” according to Hallerman.

At the same time, eMarketer revised its figures for Facebook downward slightly after the company’s S-1 filling revealed a slower-than-expected growth rate for 2011, particularly in the fourth quarter.

Last year, net U.S. display ad revenues at Google hit $1.71 billion, while Facebook raked in $1.73 billion -- helping the social network beat out Yahoo as the top seller of display advertising online.

This year, domestic display revenue growth at Facebook and Google will be nearly identical -- around 48% year-over-year -- with Facebook expected to earn $2.58 billion in revenue, compared to Google’s $2.54 billion, eMarketer predicts.

In 2011, the overall U.S. display ad market -- including Web video, sponsorships, rich media and banner ads -- grew 25.2% to $12.4 billion in 2011, eMarketer estimates -- and will increase to $15.39 billion in 2012.

Facebook’s share of U.S. display ad market revenues grew to 14% in 2011 -- up from 11.5% in 2010. This year, Facebook’s share is expected to grow to 16.8%. Google’s share of U.S. display ad revenues is expected to reach 16.5% in 2012 -- up from 13.8% in 2011, and 12.1% in 2010, when the company closed its deal to purchase mobile advertising company AdMob.

Sure to worry some marketers, Google and Facebook are pulling away from other contenders in the display advertising business. Representing immense power, Google and Facebook’s combined display ad revenues will account for 33.3% of total display ad spending in 2012, eMarketer predicts -- rising to 38.8% in 2014.

Conversely, Yahoo will see its share of the U.S. display market fall to 9.1% this year -- from 10.8% in 2011. That’s a far cry from 2008, when Yahoo’s share peaked at 18.4%, eMarketer notes. Also, Marketer expects Microsoft's share of display revenues to shrink to 4.4%, this year from 4.5% in 2011, while AOL’s share will fall to 4% in 2012 -- from 4.3% last year.