First, let's look at what someone much much smarter (and richer) (and more famous), Dave Winer, has to say:

Today, when a company raises VC, it's probably because their app has achieved a certain amount of success and to get to the next level of users they need to spend serious money on infrastruture. There's a serious economic and human wall here. You need to buy hardware and find the people who know how to make a database scale. The latter is the hard problem, the people are scarce and the big companies are bidding up the price for their time. Now Amazon is willing to sell you that, to turn this scarce thing into a commodity, at what likely is a very reasonable price. (Haven't had time to analyze this yet, but the other services are.) Key point, the wall is gone, replaced with a ramp. If you coded your database in Amazon to begin with you will never see the wall. As you need more capacity you have to do nothing, other than pay your bill.

That is all quite true, especially the part about not wanting to own guys who you only need during the predictable phase (design) and the unpredictable one (success).

But, with all due respect, I think Dave misses the point: you don't want to use Amazon for this because....

Think about what business Amazon is in:

• They own and operate a B2C website
• They run an enormous affiliate program with consumers and small businesses
• They integrate with large (and small) third party vendors to sell-through their products

Now add:

• They provide computing infrastructure

Kinda sticks out, don't it?

Let's try a thought experiment with Yahoo:

• They provide a search engine
• They sell advertising
• They sell webhosting
• They manage ecommerce stores

Hmm, the last two kind of go together as do the first two. Yahoo has 70K+ stores at $40/month each, that is at least $35M a year or so. And given their horrible recent record on being live on a Cyber Monday, seems like most of that should be profit!

Kind of kidding, but at least hosting and ecommerce is a large part of Yahoo's income. I would be shocked if Amazon's service was a rounding error on their top line, or even something that turns a profit in a ABC world.

And there you have the real reason (from a business point of view) why I'd never outsource my infrastructure to Amazon - it is simply not an important business to them, and never will be. And the "strategic" nature of it is only as good as the next Bain Consulting PowerPoint.

Now, if IBM came along with a similar scheme, I would take it very seriously because that is a HUGE business for them. I'm not against the notion (we host all our production servers and a lot of our development/test servers as well) I just don't want to get locked in a relationship where someone can, and is likely to, make a citizens divorce and toss me out on the street.