He was VP of a hedge fund, and assigned the project of investigating the potential of online commerce on the nascent Web by the company. He did so, and concluded that there was enormous potential, but after his report, the company decided to pass on it.
Clearly, he was right about the potential. If he’d been better at his job/more persuasive, D.E. Shaw & Co. would have invested in the Web, and he would not have had reason to leave and start Amazon.