From the IAB release on first quarter 2010:
Internet advertising revenues in the U.S. hit $5.9 billion for the first quarter of 2010, representing a 7.5 percent increase over the same period in 2009, according to the numbers released today by the Interactive Advertising Bureau (IAB) and PricewaterhouseCoopers (PwC). This marks the highest first-quarter revenue level ever for the industry.
You already knew this if you read my Predictions for 2010, #9.