Computer, Software, Hardware, Laptop, Printer

"We have every reason to believe, based on torrid sequential growth quarter after quarter, and year after year, that robust growth will continue," said David Doty, an IAB senior vice president.

Growth slowed compared with last year's first half, when spending increased 37 percent over 2005's first half. However, that is mainly due to the fact that spending this year is so much higher than last year, Doty said.

"The growth is on a much larger number. Both quarters and the half year are historic highs in pure dollar amounts," Doty said. "The results are very encouraging."

In the second quarter, revenue reached almost $5.1 billion. "Advertisers understand that they need to move their dollars here [to the Internet] to reach their audiences," he said.

Once again, the search ad format was the largest one, nabbing 41 percent of the spending during the first half, followed by the display format (32 percent), which includes types like video and banners.

Regarding pricing models, performance deals, such as pay per click, accounted for 50 percent of the first half's spending, while impressions accounted for 45 percent. The rest were hybrid deals involving both pricing models.