Back in 1995, I purchased a used Mac laptop via auction on the Internet. The company that enabled that transaction doesn't exist today. That same year, eBay was founded and today is worth $68 billion.
Amazon wasn't the first company to sell goods online. Google didn't invent search, and Dropbox wasn't the first server-based storage offering. Pick a successful company, and you can almost always point to the sad story of a failed predecessor that had the same core idea.
When the movie The Social Network became a commercial success, many of my friends outside of the technology industry asked me what I thought of Mark Zuckerberg stealing the idea for Facebook from the Winklevoss twins. I told them that the technology community thought the Winklevoss claim was laughable and opportunistic.
Facebook is far from an original idea. Social networks had been around for nearly a decade, in companies such as SixDegrees, Friendster, and Myspace. Facebook's success didn't come from the idea but instead from countless ideas and iterations around product implementation, go-to-market approach, and customer engagement.
In October 2002, my co-founders and I started Brontes Technologies, a company based on an invention created at MIT that used 3-D imaging to enable mass customization in the dental industry. Numerous venture capitalists passed on Brontes after their technology advisers told them that the idea behind the technology was highly risky and probably wouldn't work.