20. Joe Green

Facebook

Original Profile ID: 6

Early connection to Facebook: Green has been associated with Facebook since the beginning. He initially helped Zuckerberg with Facebook's first iteration, Face Mash. Face Mash, a hot or not for students on campus, got them in trouble with the university. Green's father didn't want him to work on anything else with Zuckerberg again.

Still, Green was around as the social network unfolded. He reflected on its founding and his part in it via a recent Facebook post: "Ten years ago today we were in our dorm room in Kirkland House and Mark Zuckerberg pushed Facebook live, and we created accounts. Then we all called and emailed our friends at Harvard asking them to sign up," Green wrote.

What he's doing now: Green is the co-founder of FWD.us and he's an entrepreneur in residence at Andreessen Horowitz.