Fueled by ad growth on Facebook and Twitter, U.S. mobile ad revenue is estimated to have surged 178% in 2012 to $4.1 billion. That figure is projected to rise 77.3% this year to $7.29 billion
before reaching $27.1 billion in 2017, according to a new eMarketer forecast.
Thanks to its dominant search business, Google is expected to lead the way in overall mobile ad sales
with nearly $4 billion, up from about $2.2 billion in 2012. Facebook will be a distant second, with $965 million, followed by music streaming service Pandora ($372 million), Twitter ($266 million) and
Apple ($213 million).
When it comes to mobile display, Facebook is expected to be on top with 28.6% share of ads in 2013, up from 21.1% last year. Google will claim 19.6%, followed by
Pandora (11%), Twitter (7.9%) and Apple (6.3%). eMarketer points out that both Facebook and Twitter have benefited from using in-stream ads, which allow them to deliver a much higher volume of mobile
ad impressions than traditional publishers.