You seem to have it mostly right, but to clear up some confusion: There's basically two directions to consider. Your circles are for your outgoing posts. When

You seem to have it mostly right, but to clear up some confusion: There's basically two directions to consider. Your circles are for your outgoing posts. When you post something, you choose which circles are allowed to see it (or you could choose individual people, or "Public"). On the flip side, your circles inform your incoming news stream. By putting someone in any of your circles, you basically say, "I could be interested in what they say." What appears in your stream, then, are posts in the intersection of the two: from someone in one of your circles, and to a circle of theirs that they put you in. So to answer your original question: Google+ can operate in the Twitter modality exactly. You put someone in any circle ("Following", by convention), and then any posts they make to "Public" will appear in your stream. The difference is that the person you're following doesn't have to direct all his posts to "Public". He or she could send some to specific groups of people, which you wouldn't receive.