The 3 Cs of Google+#newGplus #howtogoogleplusCollections:
Help you organize posts around topics, and let your followers choose what types of posts they want to see from you. If you find yourself posting a lot about a specific topic, it’s a good idea to create a collection. People who really want to read about this subject will engage more as you are providing content they are interested in, and people who don’t want to hear about it, won’t be turned off. It’s a win-win for everyone.support.google.com/plus/answer/6320409Communities:
You can have conversations with people who share your interests. Different than collections in which only the owner can post, communities allow every member to post. Advantage: invites discussions and exchange of ideas and provides different points of view on a subject. Disadvantage: requires a lot of work from the moderator to keep the posts on topic and monitoring behaviour while trying to allow everyone to express their ideas.support.google.com/plus/answer/6320411Connections (or circles):
You can add people/pages to your circles. Also called follow.
When you follow a person/page, posts they share with you will show up in your home stream, unless your settings stop this from happening.
Someone you follow doesn't have to follow you back, so they might not see what you post.
Make sure you follow because you are interested on the posts and not as a complimentary follow back. Google will suggest people, communities and collections based on who you follow. In the end, who you follow will have a big influence in your G+ experience.support.google.com/plus/answer/6320398