amazon's moat: cheap prices via the infrastructure they've built around efficient storage, warehousing, and delivery. Try finding most of the stuff they sell for materially less money once you take into account delivery costs. A deserved reputation for great customer service. Variety. Amazon prime -- $79 / year and I just don't bother shopping anywhere else. Kindle -- a 3rd gen ereader with an experience no one else replicates. Their huge marketplace of used books -- practically every text I want can be had for less money by buying used, but only on their site.
Apple's moat: for ipod: your music library that doesn't play on any other devices. Their ecosystem of products that all work together and become more valuable the more apple stuff you have. See airplay ( http://www.apple.com/itunes/airplay/ ) or how apple tv streams video from apple devices. For their laptops, as Gosling said, it's a unix with qa and taste. For iPhone, your app library, your music, and selling devices with quality and taste.
Agreed but if someone had the balls to compete with either of those, there's nothing stopping them. Zappos has shown that the way to beat Amazon is not by competing on price.
Groupon is an advertising company, which knows how to leverage technology. It's not like they invented email marketing. They just know how to use it damn well. When you are selling other people's stuff, the only limitation is how much stuff other people are selling, which is apparently infinite. See Google.
Apple's moat: for ipod: your music library that doesn't play on any other devices. Their ecosystem of products that all work together and become more valuable the more apple stuff you have. See airplay ( http://www.apple.com/itunes/airplay/ ) or how apple tv streams video from apple devices. For their laptops, as Gosling said, it's a unix with qa and taste. For iPhone, your app library, your music, and selling devices with quality and taste.