Today is the exact day (4 Feb) that Facebook was launched, only it was not Facebook.inc. And with small features. The first version was for Harvard student. And later college students with emails having .Edu ending. And then Facebook became more wider and wider. And made Mark Zuckerberg one of the youngest billionaire.
Most of the Facebook revenue comes from advertising in Facebook profile and pages.
Mark Zuckerberg had a great talent making programs. When he was still in high school, he created a network program called “ZuckNet” which allowed computers to directly communicate between home and dental place (where his father worked.
There is also a movie called The Social Network. Which you will know the start of Facebook.