Internet advertising revenues reached almost $5.9 billion for the third quarter of 2008 - an 11% increase over the same period in 2007 and two percent higher than Q2 results, according to the latest report from the Interactive Advertising Bureau (IAB) and PricewaterhouseCoopers LLP (PwC).

Data from the IAB Internet Advertising Revenue Report show that while double-digit annual growth continues, the quarter-to-quarter curve remains relatively flat compared with recent past performance.

Despite the condition of the US economy, the Q3 results still represent the second-highest quarter results ever. For the first nine months of 2008, revenues totaled $17.3 billion, up from $15.2 billion in the same period a year ago and surpassing the record set in the first nine months of 2007 by nearly 14%.

“The growth of interactive advertising that we’ve been experiencing over the past few years has stabilized due in large part to the difficult current economic climate,” said Randall Rothenberg, president and CEO of the IAB. “Interactive advertising continues to be the most measurable and cost-effective way to reach consumers, and we see more and more marketers seeking to harness its power.”

“A weakening economy will continue to be a challenge to all forms of advertising-supported media,” said David Silverman, a partner at PricewaterhouseCoopers LLP. “However, the internet should be better poised to withstand the storm given its ability to combine performance-based advertising along with broad-based branding.”

About the research: Conducted by PwC’s New Media Group, the report aggregates data from all companies that report meaningful online advertising revenues. The survey includes data concerning online advertising revenues from websites, commercial online services, ad networks, free e-mail providers, and other companies selling online advertising. Q1 and Q3 revenue reports are estimates, with actual figures released with Q2 and Q4 data respectively.