Pandora’s Discovery Weekly competitor, Thumbprint Radio, now has 20 million listeners

Publicly traded online radio service Pandora is today revealing statistics showing the growth of Thumbprint Radio, a radio station that’s customized based on users’ listening habits. It’s got 20 million listeners, with people listening for more than 373 hours thus far, just nine months after the feature launched, the company said.

Before giving you a Thumbprint radio station, Pandora needs to collect information about what you’re into. It won’t just pre-populate with random music, because it wants to be sure you’ll like what you get. If you try to sign up for a station by going to pdora.co/thumbprintradio, you’ll get an error message: “Want Thumbprint Radio? We need to know you a little bit better. Keep creating stations and thumbing up songs you love, and we’ll let you know when it’s ready!”

But, evidently, millions of people have gotten over that hurdle. People listen more than three times a week and leave the music on for an average of 40 minutes, Pandora said. That’s real engagement — last year, Google said that mobile visits on average lasted more than 40 minutes.

In a blog post today, Pandora actually describes Thumbprint Radio as “the most popular radio station on the planet.”

The question is whether users will stay with Pandora for this sort of personalized music selection, or if they’ll flock to full-blown music streaming apps, like Spotify, which has the highly regarded Discover Weekly playlist that’s replenished with new music every week, and Apple Music, which recently introduced the automatically assembled My New Music Mix playlists.

Pandora was founded in 2000 and is based in Oakland, California. Last year, it acquired key assets of music streaming app Rdio. In the three months that ended on June 30, Pandora came up with a $76.3 million loss on $343 million in revenue.