Google+ platform websites integration using the Google+ platform tag.
The Tweet Button is a small widget which allows visitors to share content and connect on Twitter.
Let visitors recommend your content on Google Search and share it on Google+.
Allows a website to define how a page is rendered in Internet Explorer 8, allowing a website to decide to use IE7 style rendering over IE8 rendering.
Open graph description entity tag
The Open Graph protocol enables any web page to become a rich object in a social graph, a open protocol supported by Facebook