A hack for Stockholm Music Hack Day.
Blobble solves the problem of scrobbling to multiple accounts when you're listening to music with friends, or in public places.
It authenticates against Last.fm and registers your phone mac address. After this has occurred, if a blobble client reports that it has scrobbled and can see your phone the scrobble will be replicated to your account, as you also heard it.
The perfect example is sitting at a friends house listening to music, everything you hear will automatically be scrobbled to your Last.fm profile with no interaction from you or your friend.
Blobble comes with an example cross-platform daemon called Blobbler that watches a Last.fm account for activity, then scrobbles that activity to any Blobble users in the area. Other Blobble clients have been written that report any playing activity in them.
Blobbler depends on Lightblue, a cross-platform bluetooth module for python. (http://lightblue.sourceforge.net/)
Right now you can't delete your information from Blobble - if you wish to stop things being Scrobbled to your account, either revoke Blobbles Last.fm access rights, or type a fake Mac address into the Blobble admin panel. I'll fix this soon.