Facebook's ImportanceFacebook is a famous and popular
free social networking website that allows registered users to create profiles, upload pictures  and video, send messages and keep in touch  with friends, family and other colleagues.
The site, what is  generally in 37 different languages, includes public features such as:
Marketplace –  permit members to post, read and respond to classified ads.Events  Groups –  permit members who have common interests to find each other and interact
.Allows members to publicize an event, allows guests and track who plans to attend.Pages –permit  members to create and promote a public  page  built around a specific topic.Presence technology – allows members to see which contacts are internet and chat.
Within every member’s privacy  profile, there are several key networking components. The maximum popular is arguably the Wall, what is essentially a virtual bulletin board. Messages left at a member’s Wall can be text, video or pictures.
Others popular component is the virtual Photo Album.  Pictures can be uploaded from the desktop or directly from a cell phone camera. There is no limit on quantity, but Facebook staff will delete  inappropriate or copyrighted images.
An interactive album feature permits the member’s contacts (who are called generically called “friends”) to comment on every others photo and identify (tag) people in the photos. Others popular profile component is Status Updates, a micro blogging feature that permits members to broadcast little Twitter-like announcements to their friends.

Facebook's Importance
All interactions are published in a News-feed, which is distributed in pure-time with the member’s friends. 
Facebook offers a distance of  private options to its members.  A member can  build all his communications  abilities to everyone, he can block specific connections or he can keep all his communications privacy. 

Members can  like whether or not to be searchable,  decide  what parts of their profile are public’s, decide what not to put in their news feed and determine certainly who can see their posts. For those members who wish to use Facebook to communicate personally , there is a message feature, which closely resembles to email.
On May 2007, Facebook opened up its  development platform to  permit third-party developers to build applications and widgets that, once permitted, could be distributed through the Facebook community.
 In May 2008, Facebook authority and engineers announced Facebook Connect, a cross-site initiative that  permits users to publish interactions with third-party partner sites in their Facebook News feed and others.