The video demo of the upcoming version of Spotify for iPhone (and iPod touch) that was yanked from YouTube has reappeared via Tech Digest. The mobile version of the streaming music service looks as polished as Mike Butcher over at TechCrunch UK first reported, although now that I’ve had a few hours to ponder its existence, I can see a number of reasons why Apple may never allow Spotfy into the iPhone App Store. Spotify isn’t the only music streaming app for iPhone (and therefore iTunes competitor) but it differs in two crucial ways:
- Unlike Last.fm or Pandora, specific tracks and whole albums can be streamed on-demand, as apposed to having to be content with the choices or recommendations of the app itself – with no limits aside from the size of Spotify’s music catalog.
- According to reports, Spotify on iPhone is able to cache tracks referenced in the playlists it creates so that the service can still be used outside wireless coverage. This solves one of the major drawbacks of streaming-only offerings and makes Spotify a much more direct iTunes competitor. Interestingly, Slacker offers similar functionality in its Blackberry mobile app but stripped off-line plackback from the company’s iPhone version.
I recently hailed Spotify as my streaming music service of choice but bemoaned the lack of a mobile version. That’s set to change, reports my friend Mike Butcher 
My music streaming weapon of choice used to be Pandora, the Music Genome Project-based service in which a group of experts have analyzed the component parts or ‘genes’ of thousands of tracks in order to recommend like-minded music. I not only found its recommendations (play tracks similar to artist or genre x) to be more accurate than rival Last.fm, but also loved its simple User Interface, designed perfectly for when I’m in a lazy listening mood. The problem is that Pandora stopped being accessible from the UK a while back. Enter