Turning on notifications for communities with more than 10,000 members is really simple. Visit the community you want to start receiving notifications and just look for the button underneath the title and brief description of the community on the desktop web. Click the button to turn the notifications on, and you're all done!
It's easy to toggle notifications on and off |
If you want to make sure you are involved in the discussion of recent Google+ updates or feature updates, make sure to join our Google+ community, Google+ Updates, and turn notifications on.
Source: Brian Glick