[jstanderfer]

No one doubts that Amazon's customers love them and that Amazon is growing revenue at an incredible rate.

The question is when and if will this revenue growth translate into increasing margins? Revenue growth without profit has very little value (see Groupon) and the nature of their current businesses make it difficult to establish a competitive position where you can increase margins by charging a premium versus your competitors.

For reference - Wal-Mart has operating margins of 6x those of Amazon, has 8x as much revenue as Amazon yet is only valued at 2x that of Amazon. It would take Amazon almost 8 years of nearly 30% growth in revenue and profit margin to match Wal-Mart, a company which trades at a PE in the low teens.