Spotify, a web-based music service, has announced the latest update to its free mobile application for wirelessly streaming music. Spotify 0.4.5 adds support for several new social features that have recently been worked into the desktop version of the software. Facebook and Twitter integration have both been added, accessible via an in-app browser, while the new Inbox feature allows users to receive track recommendations from friends. In addition, the updated application will now automatically attempt to find a replacement for any track that can't be played, and an