Google +1 (pronounced "plus one") is a recommendation button similar to Facebook Like button. Or like Google said, the +1 button is shorthand for "this is pretty cool" or "you should check this out".Similarity with Facebook Like button is both of them show friends that recommended your post. But while Facebook Like only shows them under the button in your blog post, Google +1 also shows them under your post in Google SERP (search engine results pages).
So if your friend love your content then click +1 on your post, then the +1 buttons will shows on Google search to let people know their friend recommend it.
This +1's can help friends, contacts, and others on the web find the best stuff when they search.
Google +1 will also shows in your Google+ (Google Plus) profile page. In order to show your +1's tab to the world, or keep it private you can easy set this up from +1 tab on your Google profile. Once you click +1 in any website your +1's stored in your Google profile and you can use it to manage the ever-expanding record of things you love around the web.
For more information about the +1 button, you can watch this short video:
