• by Erik Sass  @eriksass1, June 28, 2011

The popularity of online audio is matched only by the fleeting nature of deals in the space. The AOL Huffington Post Media Group says AOL Music is parting ways with CBS Radio, its online streaming audio partner for the past three years, and forming a new partnership giving streaming responsibilities to Slacker.

In addition to supporting interactive stations on AOL Music's new free ad-supported audio service, AOL Radio, the new tie-up will allow AOL Music to launch two new ad-free, customizable paid streaming audio services corresponding to Slacker's two subscription offerings: Radio Plus, available for $3.99 per month, which allows listeners to skip songs, and premium Slacker On-Demand, for $9.99 per month.

According to Business Insider, AOL Radio will re-launch both its Web site and its iPhone app later this summer to implement the Slacker partnership. Overall, AOL Radio currently features over 250 programmed online stations, reaching 3 million unique listeners per month, who listen to about 30 million hours of music.

The AOL Radio iPhone App has been downloaded more than 3 million times. Plus, the deal should more than double Slacker's listener base, per Evolver.fm.

The ability to offer listeners both customized and more traditionally-programmed audio streams has become a key feature in the success of online radio. The wide popularity of Pandora, which held an IPO earlier this month, has inspired competitors to bulk up their own customizable audio offerings.

Back in March, Clear Channel Radio acquired Thumbplay, Inc., which allows users to listen to unlimited, on-demand music -- both on- and offline -- on their computer or mobile device, including iPhones and smartphones using the Android operating system. The service includes an auto-sync feature for mobile devices, plus options for importing music from iTunes. It also has an offline mode for listening on subways, planes or other situations without mobile Internet connectivity.

Clear Channel said it plans to combine Thumbplay with its existing iHeartRadio service to create a new platform, which will power digital music operations for Clear Channel's roughly 750 radio stations nationwide, as well as a number of digital, commercial-free stations hosted on iHeartRadio.

The new platform will also allow listeners to create their own personalized "radio stations" using Thumbplay's "Playlist Genie" and "Favorites" functions.