This post will either fill you with self-deflating angst, or put a battery in your back and inspire you to get off your ass and go do something. The 10 dudes on this list did just that. They conjured up an idea and hustled to turn that shit into reality. Is it hard? Excruciatingly so. But as you'll see as you click through, all you need is an idea. Thanks to the annual Forbes list, we know who's raking in dough by the dump truck. But who are the young gunners—besides Mark Zuckerberg and his crew—that are caking off? From guys that make sites and products you use every day, to youngins that filled a niche, peep the 10 richest Internet entrepreneurs under 30 and get inspired.