Google takes more than half of the market share of mobile ads, crowding out other media companies such as Facebook and Twitter.
In contrast, Facebook has only 13-percent and Twitter has about 2-percent, according to eMarketer.
However, it should be noted that both Facebook and Twitter's mobile ad numbers were nonexistent in 2011 and have consistently grown in the next two years.
In 2011, Google had 38-percent of the mobile ad market.
Across all digital platforms, Google continues to reign as not only the largest beneficiary of digital ad spending in the US, but worldwide as well, eMarketer estimates.