It's not automatic, but it's pretty easy.

A friend of mine was contracting at an online geneology site. The president of the company was worried that on Christmas morning, when everyone opened their brand new computer, that his site would get swamped. So, because my friend was a contractor, he got to baby sit the servers and make sure everything stayed up and running. He missed Christmas morning with his small children. In the end, everything stayed running when there was no surge in usage. Had they been in Azure, he could have sat at home, enjoyed time with the kids, and monitored the system from there. Not that Azure is the right solution for the company, but there many reasons why it could be the right choice.

But there are others. Amazon and RackSpace are a couple


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>I didn't see that it was all that easy to scale up. Not automatic anyway.
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>If a retailer was big enough and had a large enough demand swing it might be justifiable. Otherwise, save the added variable monthly bills and the added development overhead and get what you need. BTW the monthly bills are purely expenses. Getting your own hardware buys depreciable assets.