Create Google Music™ playlists that automatically update from user-defined criteria.
Adds user-defined autoplaylists to Google Play Music™.
Called "Smart Playlists" in iTunes, these allow you to create a set of rules defining a playlist. Then, this extension ensures it always contain the right songs.
For example, you could create a playlist that contains highly-rated songs you haven't listened to recently. Or, you could create one with all your highest rated songs of a particular genre.
Now that Google Music has shut down it's available for free. This store listing may be removed in the future.