These People Became Stars In Tech Before They Turned 21

Dan became news when the co-founder of YCombinator's 42 Floors posted a plea that begged Dan to join his company. He just finished his sophomore year at UPenn, where he is studying philosophy. He's spending the summer in Philadelphia, working on a startup called Airtime for Email that he co-founded with two Wharton students.

Sahil dropped out of USC to be Pinterest's main designer. He also built turntable.fm's mobile app. His current project, Gumroad, makes selling things as easy as sharing things on Twitter and Facebook.

Facebook launched on February 4, 2004, three months before Mark turned 20. He spent that summer in Palo Alto expanding and perfecting the social network that recently IPO'd at a valuation above $100 billion.

Eric made a name for himself by squatting in AOL's Palo Alto office for two months. There he built his education startup, ClassConnect, which he had been working on since 10th grade.

With Napster, Shawn and Sean started a fight with the music industry that's still raging. They met online four years before they launched their peer-to-peer filesharing service.

Gross was admitted to Y Combinator when he was 18, becoming the youngest founder to attend the program. He left Israel for San Francisco just before his mandatory term of military service was set to begin.

Alex, son of marketing wiz Seth Godin, taught himself to code in 7 days over a school break, and then was admitted to Tech Stars NYC. He also started a DJ business when he was 14. His current project, Dispatch.io, is a cloud-sharing service.

Andrey is responsible for the random videochatting service, which blew up in the early months of 2010. In February 2010, there were 35,000 people on ChatRoulette at any given moment.

Before he was identified, Chris became famous as moot, the moderator of the hugely popular 4chan message board. The site is a wellspring of popular memes and is the de facto headquarters of Anonymous. Chris's current project, Canvas, lets you edit pics and gifs.

13! He founded a company when he was 13. Elementeo is a chemistry card game that imagines the elements of the periodic table as monsters with stories and superpowers. Anshul is still CEO, and now he has a TED Talk.

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