Can Google Plus button is added on a website, is good for ranking in Google SERP or Just for sharing.
Hi! You can add a G+ button by following the instruction in this page http://support.google.com/plus/bin/answer.py?hl=en-GB&p=link_page_to_website&answer=1713826
Currently Google is not ranking based on Gplus. However it is really good to share good content & drive traffic to your site. Also you can add more followers to your site & increase your brand visibility.