discoversong listens to emails, tries to find artist and song names in them, searches Rdio, and adds the results to your collection or to a playlist you specify. You can also configure your music-identifying app like Shazam, SoundHound, MusiXmatch, VCast SongID, or Sony Ericsson TrackID to send emails to discoversong. Give it a try!
Log into discoversong with your Rdio id