The vast majority of retail purchases are not conducted through Amazon. Just look at Walmart's revenue compared to Amazon's. There is plenty of room to grow.
Also, in terms of Amazon's electronic offerings (music, app store, movies, a surprisingly large amount of the Kindle catalogue etc) none of that is available outside the US and a couple of other markets, so they have lots of room to grow still.
Amazon has its challenges, but so does Google, Apple, Microsoft and every other corporations in existence. As for growth, there's plenty of opportunities for Amazon. They have their nascent streaming media business, digital goods (like books) to sell, grow their tablet and phone (?) business, build out AWS and cloud services and continue growing their online-retail market share domestically and internationally.
What if Amazon had a local warehouse and a portuguese language site for example?
For example here to import a car you must be a company with special permit.
You cannot drive a car across the border and keep it.
The result is that the Brazillian astra in Brazil costs 25k USD. That same car, from the same factory in Argentina is 15K and has better engine and airbags (the Brazillian version you need to pay separately to have airbags)
This question seems to be asked a lot, and I don't think people understand what they're asking. Market cap is shares times share price. That's all it is. You can use it as a proxy for net worth, but you don't have to.
Tons of people. Outside of the USA, Amazon is still very small, with not a significant product offering.
Where is Amazon going to suddenly start making money to justify its market cap? Suddenly increase prices and thus profit margins? Their competitors will eat them alive. Grow their business? Who isn't shopping online with Amazon already? It's just nutty. Their entire business plan is selling razor blade handles at a loss so they can sell you razors at a wafer thin margin.
Amazon is the last part of the 1990s bubble that keeps going simply because it's run very efficiently.
Oh and if the states ever get the balls to tax Amazon based on its affiliate network it has no margin to operate at all.