Worldwide social network ad revenues will reach $5.54 billion this year, eMarketer estimates, with just under half that amount, $2.74 billion, coming from the US market.

Revenue growth is solidly in the double digits in the US, but even more rapid growth elsewhere will mean spending outside the country will account for a slightly greater share each year. By 2013, non-US revenues will make up 51.9% of the total, which will hit nearly $10 billion worldwide. In the US, social networks will make $4.81 billion from ads that year.

The bulk of these dollars, in the US and around the world, will go to Facebook, while a much smaller share will go to Twitter and other social networks. eMarketer’s first forecast of ad revenues for LinkedIn predicts the site will account for 3% of worldwide social network ad revenues this year, with $140.8 million. The site has more than tripled its ad dollars in two years, though growth is tapering off.

via Social Network Ad Revenues to Reach $10 Billion Worldwide in 2013 – eMarketer.