Read the article: History of Facebook in Photos by Mark Weinberger
In 2003, Harvard sophomore Mark Zuckerberg would build a program called "Face mash." It was a Hot or Not-style app using the pictures of his classmates that he hacked from the school administration's dormitory ID files. It got 22,000 page views from 450 people in the first four hours it was up. A few days later, Harvard ordered it to be taken down, citing copyright and security concerns.