Isn't Buzz their twitter-like product? Now Buzz has hardly been a success, but it would be interesting to see how they can integrate it with Google+ since it has such a different model for communication.
I am not using Buzz, so if I am wrong please correct me, but isn't it like this: Google+ -> You opt in your followers to hear your broadcast. Google Buzz/Twitter -> Your followers opt in to hear your broadcast.
(And then there is FB with mutual opting)