Taking a closer look at the list of circles above, we see More with a small downwards-pointing arrow. Clicking (tapping the left button on your mouse) causes the lists of circles to expand, revealing all circles as follows. Clicking on Less collapses them again to the compact list as shown in the preceding screenshot.
Clicking on Incoming (second from bottom above) displays posts shared with you by people who aren't in your circles. To share a post with a specific person, mention them by name in the post using a plus
+ symbol in front of their name such as
+Ralph Roberts or
+Dolly Parton (yes, she's on Plus and quite active). ...