LinkedIn Plugins are a way to drop LinkedIn functionality into websites.
Widgets. Bring Out The Best. Highlight your strongest content with a StumbleUpon Widget on your site. Get going in just two easy steps. Start Now - Its Free!
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+.
A pingback is one of four types of linkback methods for Web authors to request notification when somebody links to one of their documents. This enables authors to keep track of who is linking to, or referring to their articles.
Open graph description entity tag