Add Google +1 Button on your Website
Similar to Facebook’s “Like” Button, Google now has +1 Button. Users can add the +1 button to any individual page they recommend on Google Sites.
To get started, you need to create a Google profile or upgrade it if already have one. When you click +1 you’re publicly recommending pages across the web. When you +1 a page, the button will turn blue to confirm that you’ve recommended it, and your +1 will be added to the +1 tab of your profile.
If you want to share right away, add a comment and send it to the right circles on Google+. If you’re not a Google+ user, you can still use the +1 button to publicly recommend pages across the Web and in Google Search.
Adding the +1 button to your site will allow your visitors to recommend it to their friends which helps more people discover it through their personalized search results. Some believe this may become another indicator of a site’s popularity and relevance.