I spent about an hour this morning playing around with the Google+ changes. They're nice but still have big issues.
My primary concern is that most people already have Google accounts. So for this to work for say 90 Minds we'd have to insist everyone use an @90Minds.com address.
Hello $50/year per person (we've been able to negotiate cheaper with Socialcast)
Then this update still doesn't resolve the issue of circles which:
a. Don't perform like groups - so if you circle me you see posts I make directly to you plus off-topic stuff.
b. Circles cannot be dynamically updated -- can you imagine trying to guide 100 people to update a circle labeled ""MAS 90 Routine""
Those would be 90 Minds two biggest show stopper problems. In my opinion insurmountable.
On a lesser scale you would also have to deal with account confusion and people needing a separate Google login for just @90minds which is a huge PITA (hello endless questions).