Here we go again. Ten years after the last era in which Amazon.com (AMZN) was a great growth stock, the WSJ's Evan Newmark exhumes some of the old arguments for why its performance is insane:

• Amazon is obviously not worth 60-times earnings.
• Wall Street analysts decide what they want their DCF models to say Amazon's stock is worth and tweak their assumptions accordingly, not the other way around. (It's the same for all stocks, by the way. That's why, why Google goes to $700, analysts have $800 targets, and when it goes to $500, they have $600 targets, and so on).
• If the company's future isn't as bright as Wall Street assumes, the stock will tank.
• And so on...

To these arguments, thankfully, Newmark adds a lesson learned the hard way by many who couldn't stop themselves from uncorking Amazon short positions in the 1990s: Valuation alone doesn't make stocks go down.

Is Amazon worth 60X earnings? As Newmark suggests, it depends on that future. We don't think the Kindle will be as big a hit as Citi analyst Mark Mahaney thinks ($750mm of revenue in 2010), and we're highly skeptical of Goldman's conclusion that Amazon can grow 20% a year for the next ten years.

That said, we can't think of too many other companies that are as well-positioned for trends in retailing, real estate, energy, and consumer spending for the next ten years. And because we don't care much what happens in the next year or two, we're willing to stomach that vertiginous valuation.

Disclosure: Henry Blodget has a long-term position in Amazon.