Internet advertising revenues continued to accelerate at an unprecedented rate in the first half of 2006, increasing 36 percent over the year-ago period.

U.S. internet advertising revenues for the first six months of 2006 totaled some $7.9 billion - a new record, and 37 percent more than in the first half of 2005, according to a report by the Interactive Advertising Bureau (IAB) and PricewaterhouseCoopers (PwC). Internet ad revenue totaled nearly $4.1 billion for the second quarter, exceeding the $4 billion mark - a 36 percent increase over 2Q05.

Internet ad revenues in the second quarter increased 5.5 percent from the first quarter - the seventh consecutive quarter of growth.

"While search advertising remains the largest format in terms of revenues [see graphic], we expect to see new formats like video ads to continue to emerge as advertisers seek to leverage the branding opportunities afforded by the growing installed base of broadband users," David Silverman, Partner, Entertainment & Media Practice, PricewaterhouseCoopers.

"Interactive continues to solidify its position as a mainstream medium," said Greg Stuart, CEO of the IAB. "This latest report is a clear indication that interactive is of increased importance to marketers."

Conducted by the New Media Group of PricewaterhouseCoopers, the "Advertising Revenue Report" was started by the IAB in 1996.