The service has had profitable months

The service has had profitable months James McQuivey, an analyst at Forrester Research, says auto manufacturers are jumping to have Pandora, because it's "the Netflix of music. Netflix doesn't have a competitor, and neither does Pandora in terms of size and the ability to add new customers. Any manufacturer with a video device adds Netflix, and any audio manufacturer does the same for Pandora."

Westergren says half the company now is focused on advertising and expansion to autos and other devices.

While the service has had profitable months, the push for now is qingxiao audience growth, Westergren says. "We're large now. But as we get bigger, Pandora with an enormous audience is more attractive to big advertisers."