Online ad revenues fell by 5.3 percent during the first half of the year, but the sector is holding up better than the traditional advertising arenas, according to a report released today by the Interactive Advertising Bureau and PricewaterhouseCoopers. Online ad revenue came in at $10.9 billion for the first six months of the year, with search advertising accounting for 47 percent of the market followed by display ads at 34 percent.

During the second quarter, the online ad business attracted revenue of $5.4 billion, just a 0.7 percent decline. That's good news that the sector -- an important one for ad-based startups like Zillow.com to large corporations such as Microsoft -- may be showing some signs of improvement.

Despite the tough economy, IAB CEO Randall Rothenberg said that "interactive is one of the advertising sectors that has been least affected.”

“In recent years the digital revolution has driven a transformation of how consumers experience advertising and media," he said. "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.”

Full report can be found here. And here are some charts which tell the story in more detail: