3. Yahoo! Buys Broadcast.com

Sale Price: $5.7 billion
Year: 2001

In the biggest payday of the first internet bubble, Broadcast.com's sale to Yahoo for $5.7 billion helped make Dallas entrepreneur and co-founder Mark Cuban a household name. Unfortunately for Yahoo!, Broadcast's primary function of aggregating internet radio broadcasts didn't enable any of the competitive advantages or sustainable business models that had been projected on to it. Today, you'd be hard-pressed to find any traces of the website's existence.