I've a few questions, if the data centre is built in the desert don't you have a number of issues?
* Latency, if you have all your data centre's located in essentially a single part of the USA (lets ignore the rest of the world for this.. regardless that there are no deserts in Europe for example) won't that increase latency quite a bit to the more further away places that want the search results?
* Bandwidth/redundancy, if you have all your eggs in one basket as it were aren't you going to have to pay extra to have lots of extra fibre laid down to be able to handle all that extra traffic? What about natural disasters, if you have all your data centres in a single location then surely you run the risk of things going pear shaped if it burns down, suffers earthquakes, aliens destroy the building etc.
* Cooling, because it's in the desert isn't a lot of the electricity that is generated going to be cooling not only the building because of the outside heat, but also the heat generated by the servers? Surely it makes more logical sense to build in a colder climate say further north and use hydroelectricity? (if you're talking of using exclusively non active polluting (and non radioactive) natural electricity solutions)