Did you know.....that every time you +1 something on Google+ it posts that item to everyone in your circles? Basically it's the same as if you share it *except* if your peeps comment on it, they're not commenting to you, but to the original poster...unlike when they comment on an item you've actually shared.
You can change that. From the Google+ homepage on the web, slide your mouse to the left edge to reveal the slide-in panel, and click on "settings" at the bottom. Scroll about half way down the page to "Apps & activities", and click on the "Manage apps & activities" button. There will be three tabs at the top of the page -- click the one labeled "Google" and click the "edit" hyperlink under "Visible to". You'll see the box displayed above, explaining what the setting does and giving an option to ratchet down the visibility of your +1's all the way to "Only you" (a really good choice).
There. Now if you want to share something with your peeps, click the SHARE button on a post and they'll be able to see it and comment back to you. When you +1 something it will only add your +1 vote and the original poster can see that, but it won't spam everyone in your circles with it.