Once upon a time there was a peer-to-peer file-sharing service called Napster, and it caught the record labels completely unawares. For years people had been ripping their CDs into MP3s, but Napster showed them how to get tracks they didn't have (illicitly). And so the universal jukebox was born – though it was quickly extinguished by lawyers.
Now Spotify is here, a completely legal service which tries to get close to that universal jukebox idea, where all you have to do is either pay a monthly fee (£10 in the UK) or listen to some ads at the start of a track (and see them on the application's interface) and you can get at a huge range of music. It's not quite every song ever made - give the folks a chance - but it's a big start.
The application you download (for Windows or Mac; or in Wine on Linux) connects to the net and streams the songs. You can create your own playlists, listen to the "radio", or – perhaps most interesting – create collaborative playlists that anyone can add to (or subtract from) once they know the URL. (In the picture, the collaborative ones are green.) And when you're playing a track, there's a link - not yet implemented - to let you buy that song from Amazon or iTunes. Logically, Spotify would get a cut of any such transaction. The files are high-quality - Ogg Vorbis (the open-source codec) at roughly 160kbps; you need about 256kbps bandwidth to get it all working.
It all sounds like Napster version 1 done right. So is there anything that doesn't work right? I asked on Twitter and found that what people wanted most was a mobile-phone version (I understand that's in the works, though it might be some way off); better recommendation; better collaborative information (so you can see who has added a track to a playlist, say); and streaming to other devices such as hi-fis. Oh, and more songs - though the classical repertoire is good - and better filtering in the searches, which tend to be overly broad - my search for King Crimson turned up tracks that ex-members had made.
As competition, there's iTunes, of course, and eMusic, and Napster (now on life support from Best Buy) and so on. But those don't have the serendipity this offers. Closer might be Last.fm, which has an enormous following; or Deezer, which also offers free registration, and plays through your browser. The weakness of the latter is that it can suck up all your browser's memory. A separate application - as Last.fm offers - means you can kill that process alone.
Finally? A promising service that needs to persuade people it will still be around in a year. That's a big challenge in 2009.
Pros: low bandwidth; broad range; collaborative playlists; nice UI
Cons: limited social networking; can suck up CPU and disk
spotify.com