Kevin's rebuttal was pretty good but I'm picking a small bone with him when he says, "Firstcomer to new tech is a big advantage, and Amazon was the company to first create an outstanding combination of retail platform and decent device."
Sony was far earlier to market with e-readers than Amazon. Their hardware started better than Amazon's in many ways. Their e-store was not wonderful but it wasn't horrible either. Their PC software was a weak spot but it doesn't explain why Sony's e-book store got their lunch eaten by Amazon and why anyone seeing me using a Sony e-reader asked if it was a Kindle.