You don't need to pity Mark Zuckerberg, the billionaire whiz kid who may have gotten himself in over his head when taking the world's largest social playground to the stock market. As in, way over his head. He'll be okay. But that $38 IPO price, which was supposed to be just the beginning of a much, much higher number? It seems like a distant memory just four short months later. For one reason or another, Facebook's share price keeps moving further away from its IPO price, having started the week off by dropping more than 9.1 percent to $20.79 on Monday. Today it's down slightly more, and some are saying it could fall to $15.