Given what happened with Adobe's 'cloud' recently, i'm sure people will be rushing to trust even more of their data to this sort of thing... not.

Seriously though, personally i'm all for rentable, adaptable computing resources. Right now, we buy computing power in a sort of 'worse case' approach which is a criminal waste of money IMO. Being able to dial up only as much power as you need is a neat and elegant idea. But it's very half baked right now and a lot more work is needed in the infrastructure before it becomes a viable alternative.