Online ad spend grew to over $20 billion in the US in H1 2013

"Internet ad revenues surged to a landmark $20.1 billion, according to the IAB Internet Advertising Revenue Report released today by the Interactive Advertising Bureau (IAB) and prepared by PwC US. This represents an 18 percent increase over last year’s first-half ad revenues of $17 billion.
Maintaining the trend, second quarter 2013 internet ad revenues also saw an 18 percent year-over-year increase, reaching $10.3 billion, up from $8.7 billion in Q2 2012.
Report highlights include:
Mobile revenues soared to $3 billion in the first half of 2013, representing triple-digit growth at 145 percent, from $1.2 billion in the same period last year
Digital video, a component of display-related advertising, took in $1.3 billion in revenue during the first six months of 2013, an uptick of 24 percent over the first half of 2012 at $1.1 billion
Search revenues in the first half of 2013 totaled $8.7 billion, up 7 percent from $8.1 billion in the first half of 2012
Display-related advertising revenues in the first half of 2013 totaled $6.1 billion, accounting for 30 percent of revenues in the time period, up 9 percent from $5.6 billion in the first half of 2012
The top three advertising verticals accounted for 46 percent of advertising revenue, including Retail at 20 percent, Financial Services at 14 percent and Automotive at 12 percent
 “Digital has steadily increased its ability to captivate consumers and then capture the marketing dollars that follow,” said Randall Rothenberg, President and CEO, IAB. “Mobile advertising’s breakneck growth is evidence that marketers are recognizing the tremendous power of smaller screens. Digital video is also on a positive trajectory, delivering avid viewership and strong brand-building opportunities.”
“This report not only confirms that brands are making a greater commitment to interactive, but also points to the fact that mobile and digital video are being identified as integral elements of the marketing mix,” said David Silverman, a partner at PwC US. “Internet advertising’s ability to impact and engage is evident across digital screens, whether big or small.”
“Consumers are embracing new screens, new content and transforming how they shop, communicate and consume content at an accelerated clip,” said Sherrill Mane, Senior Vice President, Research, Analytics and Measurement, IAB. “And, in response, marketers are turning to those same interactive arenas just as quickly.”"
Source:  Data from the IAB & PwC, reported in a press release, 9th October 2013
Note - full breakdown over time and by format in the full press release