Water, Electricity - and Computing?

When electricity first came into widespread use in the home and in industry, there were no central power stations and no National Grid. Each country house, each factory and each small town had one or several generators supplying less than perfectly reliable DC electricity. Over time, AC was developed and larger power plants supplied electricity that could be sold on a meter. A grid of cables was installed to make it easy for consumers to buy as much electricity as they needed, with as little effort as turning on a switch. Why would we ever go back to generating our own electricity when it is so reliable, relatively cheap, we have a choice of suppliers and it is very Green?

So think about computing. The boxes are commodities, we can rack them up and most of us don't really care about the inner workings; we just want them to make our business applications function reliably and quickly. And while we are on that subject, why do we have to buy our own applications, why can't we tap into those as well? My crystal ball tells me that it won't be long before computing power is sold like electricity, and applications too. But hey, what is all that I'm reading about Cloud Computing, SaaS (software as a service), Utility Computing and Grid Computing? It's nearer than you might think.