Jsut to add to the discussion, I am a regular contributor (and community moderator) on Google+. Its' an exceptionally good, rapidly growing social platform, but it really depends on a great deal of interaction. You will only get out of it what you put in.
My recommendation would be to join, look under the 'Communities' tab and search for subjects you are interested in. Then, join those communities, post interesting, relevant content and join the discussion. Google+ can also be a good place to share your hubs, so long as they add value to the community you are participating in - If they don't, they will be ignored / deleted.
If you can build up a reputation as a good contributor and sharer, followersw ill come, people wil start to trust your opinion and if you link Google+ to your author profile, that will also benefit you in search results as author rank becomes morea nd more important.
Hope this helps.