Twitter is outpacing Facebook in US mobile advertising revenue this year, according to a survey released Thursday showing a market dominated by Google.
The report by the research firm eMarketer said Facebook, which just rolled out mobile ads for the first time this year, will likely overtake Twitter by 2013 but will not come close to matching Google.
The report estimated Google will take in 2012 mobile ad revenues of $1.4 billion, or more than half the total for the United States of $2.6 billion.
Internet radio group Pandora is expected to be second with $226 million, followed by Twitter with $129.7 million.
Facebook was expected to see some $72.7 million from mobile ads, just behind Apple's $75 million, the survey indicates.
But eMarketer forecast that Facebook will rise to number two in the US market by 2013 with $387 million in mobile ads and will take in $629 million by 2014.
Twitter gets revenues from mobile through so-called "promoted tweets," which make up a large portion of the group's revenues, eMarketer said.
Facebook gets most of its revenue from its Marketplace advertising platform, mostly ads that display on the right-hand side of Facebook's desktop experience, but not mobile.
Facebook recently began placing ads in the user's newsfeed, including on mobile devices.