This came out of the blue... and while it may not be quite the update we anticipated (or necessarily wanted) it is an update that will send shockwaves about the Web.
Spotify has moved from beta version 0.32 to 0.4.3, yes really. Thankfully Spotify doesn't play by conventional version numbers though, since 0.4.3 is easily the streaming music platform's biggest update since its launch in October 2008.
The big news is 'Spotify Social' - Spotify's new social networking system. This is primarily done through integration with Facebook and brings a new 'people column' to the player which shows a list of all your Facebook friends using Spotify and what are their 'Top artists' and 'Top tracks'. Their playlists are also shared and these can be subscribed to and viewed along with a 'Feed' showing you what music your friends are talking about.
Naturally the public nature of these can be individually edited so you can hide that disturbing Carly Simon obsession from view. On the flip side, you can subscribe to profiles like that of Sean Adams from Drowned In Sound and keep up to date with the site's monthly top track picks.
Extending this social networking further is the addition of an 'Inbox'. Any tracks or albums you like can be dragged onto any of your friends in the people column and that content will turn up in their inbox. Clever stuff and a nice extension of the ability to use http links to share Spotify files in the past (that remains intact).
Major change number two is the 'Library' feature which gives you the option to scan your computer for music files and integrate them into your Spotify library. Your library can then be played directly from Spotify and - in a neat twist - synced with Spotify's mobile client if you add it to a playlist. If you make this playlist available offline this even works when the artist isn't on Spotify since it will wirelessly upload the content from your computer.
Other bits and pieces? You can now star your favourite tracks, shared playlists show their number of subscribers so you can see how popular your selections are and you can search for individual Spotify users with the command 'spotify:user:username'.
On the downside, Spotify seems to have taken something of a Google Buzz approach to social networking by sharing all your information automatically and relying on you to remove anything inappropriate. Top Artists and Top Tracks also contain a few glitches (apparently my favourite track comes from a Twin Peaks soundtrack I've never hear). It has also failed to give the playlist system a much needed makeover and they remain the same ugly list system as existed previously.
Despite that, this is a welcome and potentially game changing move from Spotify and if it could integrate podcasts and device syncing perhaps we could finally be freed from the horrors of iTunes forever...