Mark Elliot Zuckerberg is an American computer programmer and Internet entrepreneur. He is a co-founder of Facebook, and currently operates as its chairman and chief executive officer. His net worth is estimated to be US $75.2 billion as of January 2018, making him the fifth richest person in the world.

Mark Elliot Zuckerberg was born on May 14, 1984, in White Plains, New York, into a comfortable, well-educated family, and raised in the nearby village of Dobbs Ferry. His father, Edward Zuckerberg, ran a dental practice attached to the family’s home. His mother, Karen, worked as a psychiatrist before the birth of the couple’s four children—Mark, Randi, Donna and Arielle.

Zuckerberg developed an interest in computers at an early age; when he was about 12, he used Atari BASIC to create a messaging program he named “Zucknet.” His father used the program in his dental office, so that the receptionist could inform him of a new patient without yelling across the room. The family also used Zucknet to communicate within the house. Together with his friends, he also created computer games just for fun. “I had a bunch of friends who were artists,” he said. “They’d come over, draw stuff, and I’d build a game out of it.”

After attending Phillips Exeter Academy, Zuckerberg enrolled at Harvard University in 2002. On February 4, 2004, he launched thefacebook.com (renamed Facebook in 2005), a directory in which fellow Harvard students entered their own information and photos into a template that he had devised. Within two weeks half of the student body had signed up. Zuckerberg’s roommates, Dustin Moskovitz and Chris Hughes, helped him add features and make the site available to other campuses across the country. Facebook quickly became popular as registered users could create profiles, upload photos and other media, and keep in touch with friends. It differed from other social networking sites, however, in its emphasis on real names (and e-mail addresses), or “trusted connections.” It also laid particular emphasis on networking, with information disseminated not only to each individual’s network of friends but also to friends of friends—what Zuckerberg called the “social graph.”

In the summer of 2004 the trio moved their headquarters to Palo Alto, California, where Zuckerberg talked venture capitalist Peter Thiel into giving them seed money. Zuckerberg dropped out of Harvard to concentrate on the fledgling company, of which he became CEO and president. In May 2005 Facebook received its first major infusion of venture capital ($12.7 million). Four months later Facebook opened to registration by high-school students. Meanwhile, foreign colleges and universities also began to sign up, and by September 2006 anyone with an e-mail address could join a regional network based on where he or she lived. About that time Zuckerberg turned down a $1 billion buyout offer from Yahoo!, but in 2007 Facebook struck a deal with Microsoft in which the software company paid $240 million for a 1.6 percent stake in Facebook; two years later Digital Sky Technologies purchased a 1.96 percent share for $200 million. In 2008 Zuckerberg’s new worth was estimated at about $1.5 billion. After Facebook’s initial public offering (IPO) of stock in 2012, Zuckerberg’s net worth was estimated at more than $19 billion.

Since 2010, Time magazine has named Zuckerberg among the 100 wealthiest and most influential people in the world as a part of its Person of the Year award. In December 2016, Zuckerberg was ranked 10th on Forbes list of The World’s Most Powerful People.