This is a guide for setting up rdio in ubuntu. Specifically via gnome-shell as an application.
Install Google Chrome on linux
Download Rdio's icon. Place it in ~/.local/share/icons/rdio.png.
Place the attached rdio.desktop in ~/.local/share/applications/rdio.desktop.
Place the attached rdio-pause in your home directory, for example ~/bin. Mark it as executable. Open System Settings and choose Keyboard. Choose Shortcuts tab then Custom Shortcuts section. Add a shortcut named Rdio Play-Pause, and give it the full path to rdio-pause. Bind this to your play/pause key. You'll need to install xdotool for this to work.

Thanks for this. I made a small change to catch all the variant title bars (ie "Heavy Rotation - Rdio"):
xdotool key --window $(xdotool search --name .Rdio | head -1) space
xdotool key --window $(xdotool search --name .Rdio | head -1) Right
xdotool key --window $(xdotool search --name .Rdio | head -1) Left