What is Google's sustainable advantage ?

Curt Monash asks what Google's sustainable advantage is over the long term and why couldn't Microsoft, given sufficient deployment of resources, be able to deliver search just as well as Google can.
First lets establish that in the very long term no advantage is sustainable in any absolute sense. That said, google’s main advantage in the search business is its ability to deploy enormous amount of computing power at low cost ( relative to industry) using its homespun set of technologies. This article describes it well. Being the lowest cost provider of computational infrastructure for mass usage makes it easy for it to maintain leadership in search which demands exactly this. However, in the future, it also enables it to go into any other areas where huge amounts of data storage, processing and analysis are required ( video is an obvious here). Sure, other companies can do this by throwing money at the problem - but can they do it at the low cost that google can ? Till there is some ground breaking technical breakthrough that makes Google’s model of distributed computing at a mass scale deployed on inexpensive hardware obsolete, I think this is as sustainable an advantange as any other.