At some point, the reach for control of e-commerce has to be supported by profits to justify this kind of p/e. Also remember the headwinds that will be caused by higher tax burdens this year. Increases in sustainable rate of growth or much better profits wil be needed to keep share price above $300.
In the not too distant future, significant increases in sales taxes will be a margin killer for amazon, and that should be a substantial competitive disadvantage for them. They could not expect customers to not be concerned about increases in costs of their purchases, regardless of any gimmicks I can foresee or being implimented by amazon. This should fare positive for brick and mortar retailers. I would like to see how they(amzn) will be profitable any time soon. Forget about $5.00 eps by the end of Fy' 2014.