Google earned more than half of the $8.8 billion spent on global mobile Internet advertising in 2012, according to eMarketer’s first study on worldwide digital and mobile advertising. Google took in nearly one-third of all digital ad dollars spent worldwide. The market research firm notes that Google earned $4.61 billion in mobile Internet ads last year, three times its 2011 earnings. This year’s total mobile revenues are estimated to be up 92.1 percent to $8.85 billion.

“After making nearly half a billion dollars worldwide on mobile ads last year, Facebook — which had no mobile revenue in 2011 — is expected to increase mobile revenues by more than 333 percent to just over $2 billion in 2013, and account for a 12.9 percent share of the global net mobile advertising market,” reports eMarketer.

According to its estimates, eMarketer suggests Twitter will also experience a worldwide mobile ad spending share increase in 2013 to about 2 percent of the total, and a 3.6 percent share in the U.S.

“Combined, three companies — Google, Facebook and Twitter — account for a consolidating share of mobile advertising revenues worldwide, as other players, such as YP, Pandora, Apple and Millennial Media, see their shares decrease, despite maintaining relatively strong businesses growing at rapid rates,” notes the research firm.

Google continues to lead the pack in digital ad spending across all digital platforms in the U.S. and worldwide. The company earned $32.73 billion in net digital ad revenues in 2012. “This year, Google will increase revenues faster than the overall market thanks to continued monetization of YouTube and growing adoption of mobile advertising, eMarketer believes, leading to a gain in share of the total digital advertising market.”