You've probably heard of 28-year-old Facebook CEO and founder Mark Zuckerberg, but do you know who Dustin Moskovitz is? He's another 28-year-old billionaire. A Facebook alum who left the company to work on another start-up, he has an estimated net worth of approximately $3.5 billion, according to Forbes.

http://www.bankrate.com/financing/wealth/who-are-the-youngest-billionaires/