The most important feature of Google Plus to understand is circles – the way you group people together to communicate with them in different ways.
In your Google Plus account you can create your own circles for any type of group – this could be members of your family, members of your book club, workmates, people you think are hot, celebrities, people who write about your hobby… A circle is exclusive to you. Anyone you add to a circle will see you have added them to your circles but they cannot see which circles they are in.
You can add people to more than one circle – so a person who is a colleague as well as a friend and a member of your book club might be in all three circles.
When you post content on Google, or share content from other people, you can choose which circle can see it. What this means is that anyone you have put into that circle will be able to see the content when they look at the content stream in your profile. If these people also have you in one of their circles, your content will then appear in their stream when they look at their own Google Plus account.
Think of Google Plus circles like a “need to know” list where each piece of information is for the eyes only of the people on the list. If you share a confidential file at work with a closed list of people, no one else can see it unless one of those people shares it with their own list of friends.
On Google Plus, you can prevent content being re-shared, so that it does stay visible only to the people you allowed to see it.
There are two other key options when you share content. You can choose to share with Extended Circles or to make an item Public.