A core lesson from the dot-com boom is that even if you have a good idea, it’s best not to grow too fast too soon. But online grocer Webvan was the poster child for doing just that, making the celebrated company our number one dot-com flop. In a mere 18 months, it raised $375 million in an IPO, expanded from the San Francisco Bay Area to eight U.S. cities, and built a gigantic infrastructure from the ground up (including a $1 billion order for a group of high-tech warehouses). Webvan came to be worth $1.2 billion (or $30 per share at its peak), and it had a 26-city expansion plan. But considering that the grocery business has razor-thin margins to begin with, it was never able to attract enough customers to justify spending such enormous amounts of money. The company closed in July 2001, putting 2,000 out of work.