Facebook is one of the most popular websites that offer social networking today with more than l billion users around the world. Online social networking is just like-minded people coming together for some activities, forming groups, having discussions, sharing photographs, etc. Similarly, Facebook enables all these activities by various applications(运用程序) , for example, providing forums, photo sharing options. video updating, keeping a track on all the happenings in their formed communities, people they have approved to be linked to, etc. Online gaming is one of the biggest USPs(独特的卖点) of Facebook, and indeed, games like Farmville and Mafia Wars have attracted many users to the site. Facebook also offered a brilliant platform for business to reach out to their customers.
In the beginning, Facebook was just meant for Harvard University students to find and contact fellow students. It was meant to serve the purpose of keeping track of who was new to college to get in touch with each other for project purposes.  It was an online directory(目录) , and was founded in 2004 0n the Harvard University campus. However, as soon as it was launched, almost two thirds of the total number of students registered themselves on Facebook. Mark Elliot Zuckerberg, along with Chris Hughes, Dustin Moskovitz. and Eduardo Saverin. helped in the launch of the site. To pursue this, Mark dropped out of Harvard and got into making Facebook a worldwide accessible site, and then to its current stand of being the top social networking site in the world.
Today, Facebook rules the social networking world, with one person in fourteen using it. It is also the second most popular site in the US, and is worth billions of dollars. And it has been a success story for the four co-founders, making them all accidental billionaires.
Title :  Facebook-the most popular social networking site in the world
I . Definition :
*One popular website    
Ⅱ.   :
* Enabling people to gather for      0n it
*  
* Offering a brilliant platform for businesses to reach out to their customers
Ⅲ   Birth :
* Time: in 2004
* Place:    
lV.      :
* To help students contact each other
V.      :
* Mark Elliot Zuckerberg, along with Chris Hughes, Dustin Moskovitz, and Eduardo Saverin
VI. Popularity:
* As an          : having almost two thirds of the students on it
* As the top social networking site :
ruling  the social networking ;
having over        in the world;
being       billions of dollars