A clear sign that consumers are receptive to subscription-based music streaming services is the warm welcome they have given to Spotify since its launch in the U.S. in July of this year.

Spotify has also gotten a big endorsement from Facebook, which featured the company prominently at its recent F8 developer conference as an example of the tighter application integration possible through the latest upgrade to the Facebook platform.

The Rhapsody application for Facebook now offers similar integration to Spotify's. However, Spotify is a more compelling product for advertisers because of its larger user base, said Altimeter Group analyst Rebecca Lieb.

"Spotify has 10 million global members, and part of their deal with Facebook is, if not compelling, then strongly driving those users to share on Facebook's platform," she said via e-mail. "Even with the Napster acquisition, Rhapsody can't approach those numbers."

Thus, there isn't a major brand marketer out there not having discussions with Spotify, because advertisers go where the reach is, which is on Facebook, and that is creating intense, unprecedented competition for other cloud music players, Lieb added.