Warning to all rooted Google Music users
To anyone using Google Music, recently Google changed their policies to allow only four deauthorizations each year. Previously, if you authorized more than ten devices, you could deauthorize one of them to make room for the new one.
This new policy is a problem for us rooted users because each time you flash a ROM, it authorizes as a new device. Now my device list looks like this, with 3 copies of a Samsung Captivate:
Note the orange banner at the top telling me it is impossible to deactivate one of my devices.
Now I have a Galaxy Nexus with no way to access my Google Music because I can no longer deauthorize my old phones.
More information can be found here: http://forum.xda-developers.com/showthread.php?t=1656038