• by Erik Sass  @eriksass1, December 30, 2010

Ando Media's monthly ratings for online radio produced a clear winner in October and November, with Pandora besting other major Web audio players by a significant margin in measures, including average active sessions and weekly dayparts.

However, Pandora competitors, including CBS Radio and Clear Channel Radio, scored better with average time spent listening.

Pandora dominated October online listening with an average 556,359 active sessions; the average time spent listening was at 49.8 minutes. This compares to CBS Radio's average 177,660 sessions, which includes AOL Radio and Yahoo LaunchCast. The CBS Radio properties were a bit more engaging, producing an average time spent listening of 64.2 minutes. Next up in terms of average active sessions was Clear Channel Radio, with 127,317. These sessions also garnered a longer average time spent listening: 77.4 minutes.

The Katz Online Network, which includes a number of stations not owned by Clear Channel Radio, had 167,115 average active sessions and an average time spent listening of 82.2 minutes in October.

Pandora led the pack again in November, with an average of 585,558 active sessions and an average time spent listening of 49.8 minutes. CBS Radio followed with 165,822 average active sessions and average time spent listening of 63.6 minutes.

Clear Channel Radio was third with 125,498 average active sessions and average time spent listening of 75 minutes. The Katz Online Network had 254,857 average active sessions and an average time spent listening of 84 minutes in November.