We live in a golden age of entrepreneurship. Now, more than ever before, it's easier to start a business, and easier than ever to scale that business to stratospheric heights.

Witness Uber. The darling of Silicon Valley (if not the media or the taxi industry) is just 6 years old yet has managed to achieve a market capitalization (the total value of its stock) of over $50 billion. That's 50 billion dollars in just over 6 years. That's higher than the market capitalization of GM, which was founded in 1908.

Another comparison? It took GM 30 years to reach a market cap of 1 billion. Uber? Just over 3.