Listening to music on your Windows Phone and use a Last.fm account? You'll need this app installed. ScrobbleMe is a simple app by Arnold Vink, the creator of ZuseMe and ZenseMe, which offers "scrobbling" support for all music played on the Windows Phone ("scrobbling" is basically to feed Last.fm data on your music history). Really handy if you're one to enjoy keeping on top of play counts and show friends what you're listening to. And, it works pretty well.
Xbox Music currently doesn't sport such functionality across supported platforms. We also can't (quite yet) fire up the Music app and check out what friends are listening, what we've enjoyed the most and any recommended tracks based on the collection of data (more advanced than what's presently available). It's definitely a feature Microsoft should look into to expand the service. Zune had solid foundations to a good service, it just needed to be built on.
Simply hit the button to submit the list of songs accumulated by the app and Last.fm will subsequently display all entries pumped up into the cloud. Note that the scrobbling is limited to local tracks only. Streaming isn't picked up. Be sure to download you Xbox Music playlists to get scrobbling. We'll look forward to Microsoft implementing such functionality into their music service so everything works seamlessly.
The hidden beauty of ScrobbleMe is that there's no requirement to run the app in the background. Boom, job done. Simply fire up the app whenever you feel like updating your Last.fm and ScrobbleMe will populate everything you've played on the device. It's easy to use and appears to work well. As for Xbox Music service, this is one of the suggestions we have for Microsoft to look at addressing immediately.
That's about it. Really nice and simple. Should you happen to uninstall the app, the developer notes that play counts will be reset when reinstalled. There's a backup tool published on the developer website that can provide a helping hand here.