The Google +1 button lets people who love your content recommend it on
Google search, and helps people discover relevant content—such as your
website—from the people they already know and trust. The +1 button
appears on Google search, on websites, and on ads. For example, you
might see a +1 button for a Google search result, Google ad, or next to
an article you're reading on your favorite news site.
Adding the
+1 button to pages on your site lets visitors recommend your
content, knowing that their friends and contacts will see their
recommendation when it’s most relevant—in the context of Google search
results. Content recommended by friends and family is generally more
relevant than content from strangers. For example, your friends may have
the same taste in music as you do, have their finger on the social
pulse, or know where the best shopping bargains are to be had - and so
you'll visit websites that they +1.
For more information about +1, and how it improves your SEO, visit: http://www.google.com/webmasters/+1/button/.
