Washington, Feb 23 (IANS): The online advertising business of search engine giant Google is growing faster than anticipated and is expected to surpass Facebook to be the top display ad seller in the US by 2013, a study has said.

Display ad is a form of graphical advertising on the internet usually appearing next to web content as banners or short video clips.

Research firm eMarketer said Facebook crossed Yahoo to be the top display ad-selling internet company in the US last year, and is set to continue the lead in 2012 with a revenue of $2.58 billion, Xinhua reported.

Google is expected to maintain the No.2 position in US display ad market this year with a revenue of $2.54 billion.

Google's display ad sales in the US market will increase to $3.68 billion in 2013, overtaking Facebook when the social network company's revenue grows to $3.29 billion, the study projected.

With all the online ad businesses combined, Google holds a healthy lead, as its share of the overall US online ad market is projected to increase to 44.9 percent in 2012 from 41 percent last year, thanks to the internet giant's strong mobile, display and search revenue growth.

Yahoo, which now takes a distant second place with its share expected to slide to 7.4 percent in 2012 from 9.5 percent in 2011, will be surpassed by Facebook in 2013 in terms of total online ad sales in the US market, it said.