• by Laurie Sullivan  @lauriesullivan, January 10, 2013

Music lovers tuned into Pandora, the Internet radio service, in December 2012 for more than 1.4 billion hours -- up 54% compared with the prior year. Active listeners also rose 41% to 67 million for the month. And on Dec. 24, Pandora members collectively listened to the equivalent of more than 5,692 years of music.

During the holidays, 31% of people in the West preferred new holiday tracks compared with classics. Midwest listeners were the earliest adopters of holiday music. Some 52% of people in the Northeast care about music more than food at holiday parties, compared with other regions across the U.S.

There are 67 million U.S. users, listening about 20 hours per month. One million are paid subscribers.

The company is on track to generate between $422 million and $425 million in revenue this year, according to estimates. Pandora CRO John Trimble said the Chrysler Group recently joined the extensive roster of automotive brands to integrate Pandora into its vehicle, making it the 20th automotive brand partner.

The service generates revenue from audio and visual ads, tapping into a wide audience across desktop and mobile, from cars to tablets and smartphones. Brands also run promotions to sponsor 30-day trials, Trimble said. Ads get targeted through signals from the member's registration data, such as gender, age, genre, and location. Pandora doesn't use services from companies like Triton Digital, which teamed with eXelate to target in-stream audio ads to digital radio listeners.

Pandora, spawned from the Music Genome Project, a DNA map for each musical piece, relies on word of mouth marketing, email, advertising within the music service to listeners, search engine optimization and social.