Facebook can let you share your web experience with your friends. Here are some of the Social Plugin:
A. Like Button
The Like button lets users share pages from your site back to their Facebook profile with one click.
My Comment: Why no dislike button? A dislike button can give alert to friends. And I think man won't like the websites that dislike by woman.
B. Login Button
My Comment: I want to keep my privacy.
My Comment: Nothing New
D. Activity Feed
My Comment: It is quite useful. The viewers can understand more about the website owner.
E. Live Stream
My Comment: I think they won't share porn.
Overall speaking, I think Facebook developers are very creative who create many functions that have not been heard before. Besides, Facebook is very influential that many popular websites are willing to cooperate with Facebook. This makes Facebook to be the most popular social websites.