The idea of computational and data grids dates back to the first half of the 90's. The vision behind them is often explained using the electric power grid metaphor. The electric power grid delivers electric power in a pervasive and standardised way. You can use any device that requires standard voltage and has a standard plug if you are able to connect it to the electric power grid through a standard socket.
As explained by Ian Foster and Carl Kesselman in Chapter 2 of their famous book "The Grid":"The current status of computation is analogous in some respects to that of electricity around 1910. At that time, electric power generation was possible, and new devices were being devised that depended on electric power, but the need for each user to build and operate a new generator hindered use. The truly revolutionary development was not, in fact, electricity, but the electric power grid and the associated transmission and distribution technologies".
When you use electricity you don't worry were it is produced and how it is delivered, you just plug your device into the wall socket and use it. Currently we have millions of computing and storage systems all over the planet connected through the Internet. What we need is an infrastructure and standard interfaces capable of providing transparent access to all this computing power and storage space in a uniform way.
I'd been following this for a while, but today's Herald reports that the Grid goes live in a fortnight.