Pandora's Weekly Cume Nearly 27 Million

Pandora announced Monday that its September 2012 weekly cume, the radio industry term for cumulative audience, in the 18 to 49 demographic grew 6% to 26.9 million from 25.3 million in June, as measured by Triton Digital. New York and Los Angeles are especially strong for Pandora. The service scored averaged a 1.2 AQH, or average quarter hour, in those markets in September. That means an average of 1.2% of the target 18 to 34 demographic is listening during a given 15-minute period in the top markets.

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Growth in these radio-specific metrics are important because they present Pandora in a positive light while using an apples-to-apples comparison to broadcast radio stations. "Triton's metrics have been instrumental in helping the radio advertising community finally understand the tremendous scale of Pandora," founder Tim Westergren said in a statement. "Pandora is now the largest radio station in most major markets across the U.S., across every demographic."

 The top five in Triton Digital's ranking of the top 20 Internet audio networks

Pandora once again had a big lead over Clear Channel in Triton Digital's ranking of the top 20 Internet audio networks. Pandora topped the list with 1.53 million average active sessions between 6am and 8pm, Monday through Friday. In January, Triton measured Pandora's average active sessions at 1.19 million.

Clear Channel was second with 260,000 average active sessions. Culumlus Streaming Network, which now includes the merged Cumulus and Citadel radio networks, was third with 73,000 average active sessions.

At fifth, Slacker was the top web-only Internet audio company tracked by Triton with 59,000 average active sessions. Slacker's number includes AOL Radio, which has been powered by Slacker since June 2011. But Slacker has not exhibited the same growth as Pandora this year. As measured by Triton, Slacker has had monthly average active sessions range from 52,000 in March to 65,000 in January.

The last internal metrics released by Pandora were from September: 58.3 million monthly active users, up 49% year-over-year, and 1.15 billion listening hours.