It's wonderful when startups succeed and burst into the limelight, but one of the sad facts of entrepreneurial life is that startup companies often fail. The biggest reason, according to some observers, is lack of a market for the product or service the company is building. But even in those companies that have a compelling idea and large, strong market, startups often fail to deliver a product that lives up to its expectations—or, sometimes, any product at all—before the cash runs out and investors become disenchanted. Many great ideas have withered on the vine for want of a solid product launch.