According to the new IAB Internet Advertising Revenue Report, published by the Interactive Advertising Bureau (IAB) and PricewaterhouseCoopers LLP (PwC), U.S. Internet ad revenues totalled US$10.9 billion in the first half of 2009, down 5.3 percent year-over-year.

The biggest contributors still went to search and display-related advertising. Search revenues increased slightly over last year to more than $5.1 billion in the first six months of 2009, while display-related advertising, including display ads, rich media, digital video and sponsorship, reached nearly $3.8 billion, slipping 1.1 percent year-over-year.

Digital video still has a robust growth, with 38 percent compared to the first half of 2008, according to the IAB press release.

According to IAB President and CEO Randall Rothenberg, interactive is one of the ad sectors that has been least affected in the economic slumps.

"In recent years the digital revolution has driven a transformation of how consumers experience advertising and media. As the economy improves, we're confident that brands will devote an even greater share of their budgets to reaching consumers as they make interactive media a larger part of their lives," he said in a statement.

"While the overall advertising market has continued to be impacted by current economic conditions, marketers are allocating more of their dollars to digital media for its accountability and because consumers are spending more of their leisure time online," said David Silverman, PwC Assurance partner according to the report.