U.S. Internet advertising revenue rose 37 percent in the first six months of the year, hitting a record of nearly $8 billion, according to a study released on Monday.

For the second quarter, Internet advertising revenue totaled nearly $4.1 billion, a 36 percent increase over the same period in 2005, and up 5.5 percent over the first quarter of 2006, according to a study released by the Interactive Advertising Bureau and PricewaterhouseCoopers.

Ad spending during the first six months of the year increased across all interactive channels, including search, classifieds, e-mail and display advertising; and growth in each category was roughly in line with the year-ago period.

Spending during the second quarter was $4.1 billion, marking a 5.5 percent increase over Q1, which the IAB and PwC reported in May.