Over $6 Billion for the first time ever! The market is maturing- check out this article, which features quotes from the President of the IAB.
Online Ad Revenue Up 10.6%
..from the article:
Search remains the main driver of revenue growth, showing a 19.8 percent increase over 2007. Digital video is still a small overall contributor, more than doubled its revenue with an increase to $734 million from $324 million in 2007.