If you need to keep your building cool, why not put it in a place that's freezing most of the year?
Yahoo is building a new data center in Lockport, NY, not far from Niagara Falls, that will be cooled in part by the bitter winds that blow off Lake Ontario. (As a Syracuse University graduate, I can vouch for how effective the lake wind is at cooling.)
Google had an idea to go one step further, filing a patent for an offshore data center that would use wave power for energy & ocean water for cooling. But Google filed the patent in 2008 & there doesn't seem to be any public evidence it's moving forward.
Yahoo & Google have been doing their part to reduce their carbon footprints, but what about Facebook? For its new data center, Facebook chose coal power. Facebook is now the target of a Greenpeace campaign to reject dirty coal, featuring this wicked awesome parody of the upcoming movie about Facebook founder Mark Zuckerberg, The Social Network: