It looks like some functionality has been added to the 'recent tracks' listing on last.fm that will display what is being used to play and/or scrobble the music.
Right now subsonic is reporting as "last.fm player."
It's only an aesthetic change, but I'd sure like to wear my subsonic badge proudly. Think something like this will happen? Or, even better, could we be provided with a variable string that we can set? Not sure if last.fm would like it, but it's a neat idea.
Thanks!