Songza soars in challenging online music field

Songza, a new online radio service, is leapfrogging Pandora as the most popular free music app for Apple devices.

But it immediately faces a struggle to survive in a business saddled with high royalty rates for artists.

The New York-based startup aims to re-write the songbook on how an online radio service ought to be run. One key difference: it has no mood-killing ads.

The commercial-free aspect appeals to people who have to pay $36 a year to avoid ads on Pandora, or $4 a month to Slacker, another online radio service.

The feature helped Songza get downloaded 1.15 million times in the 10 days since June 7, when it updated its iPhone app and offered an iPad-optimized version.