Proponents of the so-called “celestial jukebox” have had plenty to be excited about over the past couple of years. Online services that allow listeners to stream music “from the cloud,” coupled with broadband connections on desktops and mobile devices, have given music fans a sea of tunes to surf on-demand.

Yet the future of on-demand streaming remains uncertain. MySpace Music, a joint venture between the major labels and the Rupert Murdoch-owned social network, has underperformed, and there are rumors that the service — which originally allowed free streaming — may soon start charging. Meanwhile, Rhapsody, a company that offers subscription streaming on-demand and “tethered downloads” (as well as web radio and conventional MP3s), has had difficulty increasing subscribers. And the legal Napster has had similar troubles with customer retention. Then there’s Spotify, the much-ballyhooed Swedish “freemium” on-demand service that has taken Europe by storm. Though insanely popular across the pond, Spotify’s path to the US market (the biggest in the world) is still unclear. read more