Today Mark Zuckerberg reached a new milestone: he became the 321st richest American, being included in the Forbes 400 list. The list placed Zuckerberg’s valuation at a solid 1.5 billion dollars. Not a bad list to be on at 24 years old. Mark Zuckerberg has actually received the honor of being the youngest person on the Forbes 400 list. I’m sure Mark will be adding this honor to his job resume!