It hasn't been all that long since the last update to Rdio's iOS app, but the music streaming service is back with yet another revision today that offers some new features and minor tweaks. The big addition is a change to the way you can share music: instead of simply sharing to Facebook or Twitter (something still available through a refreshed UI), you can now share songs or albums directly with other Rdio users. That feature's already available in Rdio's
