WSJ has an independent opinion article written by Andy Kessler, The War For the Web, discussing the battle for the future of computing between Google, Microsoft, Yahoo, Amazon, and smaller players IBM, Sun. What caught my attention is in Andy's article he mentions data centers 7 times.

Today, there are several major clouds: Google, Yahoo, Microsoft, Amazon and smaller players IBM and Sun. Can there be more? Sure, but it would require a business model that could not only pay for it, but could rip it out every few years and modernize it. Google's $20 billion Web advertising business gives it the cash flow to do so. Advantage Google.
- Speed. Once you build the cloud, it's all about network operations. Whoever can deliver search results faster, wins. Users only realize this subconsciously, but it's true: Google's dominant share is as much about speed as it is for relevant results. Compare it to Microsoft or Yahoo and you'll see. Google built data centers next to waterfalls so electricity could be cheap enough to help it win the speed war.
The continuing battle between Microsoft and Google will mean fierce competition – adding features, building data centers, cutting deals and spending money on speed and customer convenience. That's the way to move technology forward. It's great to see Microsoft with some fight left in it. Not only hasn't the Internet yet matured, it's becoming an ever-more high stakes game.

This article helps to highlight a Green Data Center is part of a corporate strategy for Google, Microsoft, Yahoo, and Amazon to win the war, they need to be efficient with their resources. The most precious resource is power. Network is second, and water is going to quickly rise as another critical resource.