FACEBOOK

Social plugins let you see what your friends have liked, commented on or shared on sites across the web.
Like Button
The Like button lets users share pages from your site back to their Facebook profile with one click.
Send Button
The Send button allows your users to easily send your content to their friends.
Follow Button
The Follow button allows people to subscribe to other Facebook users directly from your site. (This used to be called the Subscribe Button.)
Comments
The Comments plugin lets users comment on any piece of content on your site.
Activity Feed
The Activity Feed plugin shows users what their friends are doing on your site through likes and comments.
Recommendations Box
The Recommendations plugin gives users personalized suggestions for pages on your site they might like.
Recommendations Bar
The Recommendations Bar allows users to like content, get recommendations, and share what they’re reading with their friends.
Like Box
The Like Box enables users to like your Facebook Page and view its stream directly from your website.
Login Button
The Login Button shows profile pictures of the user's friends who have already signed up for your site in addition to a login button.
Registration
The registration plugin allows users to easily sign up for your website with their Facebook account.
Facepile
The Facepile plugin displays the Facebook profile pictures of users who have liked your page or have signed up for your site.