If you've been on Facebook, the Google Plus Stream works in a similar manner. People post updates (a few words or many about what's happening in your life or anything else)—which may include photos, videos, and web links.

The major difference here is we control which posts we want to see! In the following screen capture, I've selected Stream, which shows all my circles and all public posts (tell you about those in a moment). On the screen, the circle selected (Stream here) is shown in red.

Should I want to limit the posts streaming by, it's easy to select Friends or Family or any of my circles by left-clicking on the title. Currently, only one circle at a time may be selected in this manner. Again, Stream shows them all.