According to a new report from AccuStream Research, Internet radio streams increased 37.6% in 2008, while audio ads sold against this usage rose 46.1% to $74 million.

The report "Online Music Spins and Media Spend: 2003 - 2012" cites AOL's Shoutcast service as drawing the most traffic, with 52.5% of the total streams. Clear Channel stations come in second, at 7.8%.

However the report also credits the Clear Channel web streams for bringing in the most audio ad revenue. Clear Channel leads the list of ad-supported streams with a 16.5% share, with Shoutcast following at 13.2%. However ad-supported music streams fell, as it has every year since 2005, reaching 44.2%.

On the plus side, sell-out rates improved to around 45%, up from 35% in 2007, and is forecasted to hit 50% by the end of this year, with CPMs in the $2 - $10 range for in-stream audio and $20 for video.