Google has announced a few updates to Google+ notifications, aimed at improving the signal-to-noise ratio on the social network. The new features build upon the "volume sliders" Google added to its circles in December: users will be able to choose which circles they receive notifications from and mute notifications from certain users entirely, though their posts will still surface in activity streams. Another new option will allow a user to send an email to select users, alerting them of new posts. The updates will be trickling out to users gradually over the next two days.