Here is an example of the four Privacy Levels of Google Plus Communities
I added color codes that should help for orientation. I also add the Level of Privacy L1, L2, L3 or L4 to the community title, this helps when you create and share a post that you do not get the wrong visibility level when you type in the autocomplete field to which community you share/post.
L1 - Example Public Open
anybody can join
L2 - Example Public Moderated