Spotify offers offline mode

As we predicted back in the summer, Spotify is now taking on iTunes as a rival for your digital music library. The only major feature it's lacking is CD burning. But then all your music is in a DRM encrypted format, so you'll lose it when you leave.

Basically it's the iPhone capabilities for the desktop - only with a peculiar restriction. Only 3,333 songs can be stored at a time. That's less than half the size of the average digital music library of a 14-24 year old.

UK Music's annual survey (this one ) published in August found that the average size of a collection is 8,159 tracks, of which around 1,800 are carried on an iPod, mobile phone or other MP3 player. Spotify's premium subscribers appear to be older, and have even larger collections.

Still, it's a start - and once you're a subscriber Spotify's offline mode allows you to 'dial an album' to listen to on the way home at no extra cost. That's something Apple can't match.

iTunes was developed as a side project by Apple OS engineer Jeff Robbin, and originally marketed through independent software developer Casady & Green as SoundJam. Apple acquired the rights to SoundJam in 2000, and launched it as iTunes 1.0 the following year.

It's always had CD burning, internet radio, and song ratings, and over the years has acquired dozens more minor features. But reviewing the changelog from v1.0 to v9.0 it's remarkable how irrelevant most of these are to most people. Party shuffle? The Genius?

Maybe Spotify should start working on a really trippy visualiser. ®