Mark Zuckerberg Facebook's Mark Zuckerberg hasn't turned 25, but he's already proved you don't need years of work experience under your belt to become the world's youngest self-made billionaire.

Mark Zuckerberg
CEO and co-founder of Facebook
Founded: May 2004

"Facebook's mission is to give people the power to share and make the world more open and connected."
--Mark Zuckerberg

One might assume that information would abound on the founder of a high-profile, multi-billion-dollar social networking site. Wrong. Information on Mark Zuckerberg is surprisingly scarce. Maybe that's just because the 31-year-old Harvard dropout has only ever held one job: CEO of Facebook.

Zuckerberg grew up in the New York City suburb of Dobbs Ferry, N.Y., and attended the Phillips Exeter Academy in New Hampshire. His father is a dentist, his mother a psychiatrist, and he has three sisters. He taught himself how to program computers, and during his senior year in high school, he and fellow hacker-programmer Adam D'Angelo caught the interest of AOL and Microsoft by creating a Winamp plug-in that could build customized playlists.

But both turned down job offers in order to attend college in 2002 -- Zuckerberg to Harvard and D'Angelo to CalTech. But Zuckerberg's undergraduate career in computer science wasn't destined to last. Not content to just study programming, he created a photo-rating site called Facemash, using photographs of other Harvard students from the school's online facebook (a yearbook-like publication designed to introduce students to one another). But he created his program by hacking into student records and using photos without permission, and was reprimanded by the administration for violating privacy rules and breaching computer security.

Zuckerberg, however, wasn't deterred. He eventually finished the platform for "The Facebook" (sometimes at the expense of attending class), combining the concept of traditional facebooks with large-scale social networking sites like Myspace and Friendster.

In February 2004, Zuckerberg launched the program from his dorm room with co-founders Dustin Moskovitz, Chris Hughes and Eduardo Saverin. In just a few weeks, more than half the school had opened accounts. The group quickly expanded to more universities and colleges, and that summer, Zuckerberg and his team moved to Palo Alto, Calif., renting a sublet and hooking up with investors like PayPal co-founder Peter Thiel and Napster co-founder Sean Parker.

By August 2005, Zuckerberg had officially changed the company's name to Facebook, and after raising $12.7 million in venture capital, was ready to move the company to the next level.

The site gradually expanded from college networks to include high school and work groups, and in September 2006, anyone with an e-mail address was allowed to join. Today, Facebook has more than 2.45 billion active users, and is the third most visited website in the world, behind only Google and YouTube.

Of course, Zuckerberg's success hasn't been without some controversy. Some of his college peers have accused him of stealing the code for Facebook, a controversy that was highlighted in the 2010 feature film The Social Network. After the filn's debut, brothers Cameorn and Tyler Winklevoss settled their lawsuit with Facebook, receiving $20 million in cash and approximately $45 million worth of Facebook stock at the time. Zuckerberg also caused a media furor when he introduced the Newsfeed function, which shared all activity updates between people in their respective social networks--at first without a privacy option.

In response, Zuckerberg said in a New York Times article that "Facebook has always tried to push the envelope. And at times that means stretching people and getting them to be comfortable with things they aren't yet comfortable with. A lot of this is just social norms catching up with what technology is capable of."

Regardless, the tech titans took notice. In 2006, Zuckerberg astonished the world by turning down Yahoo's offer to buy Facebook for $1 billion. A year later, Microsoft purchased a 1.6 percent stake in the company for $240 million. Zuckerberg's bet on himself paid off handsomely. On May 18, 2012, Zuckerberg took Facebook public with an initial IPO of $38 per share. The IPO raised over $16 billion, instantly making Zuckerberg one of the richest men in the world. Using that capital, Zuckerberg turned Facebook into an acquisition machine, buying out companies before they grew into full-fledged competitors. Zuckerberg used $1 billion in Facebook stock to puchase Instagram, the hugely popular photo sharing app. In 2014, Zuckerberg paid $19 million in stock to purchase WhatsApp, the widely used global text and voice app often used to send messages and make calls both domestically and internationally.

In less than two decades, Zuckerberg has turned Facebook into a nearly indispenasble part of modern life. In doing so, it has colllected and monetized your personal data unlike any other company in the world. What was once a harmless place to share family photos has now become the center of endless debates about privacy and even political influence. The company expects to receive over $400 million in political ad revenue alone in 2020. Even more controversial in nature, Facebook has attempted to remain politically agnostic, accepting the money of all parties, even if their ads prove to be knowingly false or misleading in an attempt to persuade voters. In an effort to highlight the practice, Elizabeth Warren, a candidate for the Democratic presidential nomination in 2020, placed an intentionally false ad claiming that Zuckerberg was backing Donald Trump for re-election as President of the United States. Zuckerberg and Facebook refused to take the ad down. "Some people accuse us of allowing speech because they think all we care about is making money, and that's wrong," Zuckerberg said on a Facebook earnings call. "I can assure you that from a business perspective, the controversy this creates far outweighs the very small percentage of our business that these political ads make up," said the man whose company took in $69.7 billion in revenue in 2019.