After adding Facebook “Like” button to my blog I’ve decided to add Google+1 button as well 
. I guess I am also going social although a little old fashioned with blog.
Again it is very easy to add it with two simple steps:
1. Add the tag to the template in order to appear in every post.
Open ~/themes/MY-BLOG_THEME and edit PostView.ascx by adding following script where appropriate:
<!-- Place this tag where you want the +1 button to render -->
<g:plusone size="small" annotation="inline" href="<%=Post.PermaLink %>"></g:plusone>
2. Add google JS at the end of the page.
Open ~/themes/MY-BLOG_THEME and edit site.master and add this at the end:
<!-- Place this render call where appropriate -->
<script type="text/javascript">
(function() {
var po = document.createElement('script'); po.type = 'text/javascript'; po.async = true;
po.src = 'https://apis.google.com/js/plusone.js';
var s = document.getElementsByTagName('script')[0]; s.parentNode.insertBefore(po, s);
})();
</script>
Please refer to google documentation for more information and to configurator to customize.