People often get confused with Google+ as it’s a different concept than Facebook. On Facebook, you are either Friend of not but on Google+, you create your own circles than can overlap or not.
Find out how to create Circles here:
What I like the most on Google+ are “Communities”. You have the ability to join or create and have various privacy settings.
It’s interesting as a collaborative platform where you can share resources such as pictures, videos and you can comment. You can interact with other members. A Community can be private or public or even moderated (people can ask to join).
Here is a video explaining the collaborative potential of Google Communities: