The Interactive Advertising Bureau (IAB) has released its annual report on US internet advertising revenues, claiming that they rose 22% in 2011 to $31.7bn. Of that, $1.6bn was mobile advertising, which increased 149% year-on-year. Of the overall revenues, search accounted for 46.5%, while display-related ads including banners, rich media, digital video and sponsorship accounted for 34.8%. In terms of who spent money on internet ads, entertainment companies spent $1.2bn (4% of overall spending) while media firms spent $1.5bn (5%). “This historic moment, with an especially impressive achievement in mobile, is indicative of an increased awareness from advertisers that they need to reach consumers where they are spending their time–in digital media,” says IAB boss Randall Rothenberg.