Facebook closes in on Google for mobile-ad supremacy in U.S.

There is a fundamental shift in how mobile ads are spent.
A new report by market researcher IDC contends Facebook, Pandora and Twitter are rapidly taking over the multibillion-dollar mobile-display ad market in the U.S. at the expense of ad networks such as Google, Apple and Millennial Media.
Publishers Facebook, Twitter, Pandora and The Weather Channel registered strong sales last year, controlling 52% of U.S. mobile display ad spending in 2012, compared with 39% in 2011.
Facebook racked up $234 million in revenue, followed by Pandora ($229 million) and Twitter ($117 million).
Facebook's cause has been aided by the return of General Motors, which ditched the social-networking company in a high-profile breakup only to now test mobile advertising on Facebook.
On the ad network side, Google was tops, with $243 million, followed by Millennial Media ($151 million) and Apple ($125 million).
Mobile ad spending in the United States remains strong: it grew 88% in 2012, to $4.5 billion. IDC expects growth of 55% to 65% this year, to about $7 billion, and for Facebook and Twitter to expand their businesses.
Globally, Facebook is expected to rake in $1.53 billion in mobile advertising revenue this year, up from just $470.7 million last year, according to eMarketer. In 2014, Facebook could reach $2.7 billion.