I think it's a competitive advantage that both Amazon and Google and other tech companies have over a lot of their counterparts. They take big risks and are pioneering new markets with the promise of big rewards. It's why Amazon is kind of reliably starting new businesses and opening kind of new frontiers.
There are lots of lessons to learn from Amazon. Never stop innovating or questioning the fundamentals of your business. Disrupt yourself before others do. Continually motivate employees so that they never get too complacent - see Yahoo, AOL and many other Internet companies for evidence of what happens when they do.
There are lots of retailers that are now scrambling to emulate the Amazon model, so Amazon does not have a monopoly on same-day distribution or broad selection or low prices. All that said, there are advantages that accrue to the largest player, so I don't see much in the way of Amazon slowing down.
We see Google experimenting in so many places outside of its core search and advertising business, whether that's bringing broadband Internet to the world or funding an entirely separate company to pursue solutions to disease and mortality. Amazon's one of the few other companies that thinks as big as Google does.