writes "Recent commentary at Nature Climate Change describes an on-going debate about the energy savings associated with the background colors used by high-traffic websites such as Google and the NYTimes. A back of the envelope calculation has suggested energy savings of 750 Megawatt hours per year if Google switched their background from white to black. In response, a new version of Google called Blackle was created. However, other calculations by the Wall Street Journal suggest minimal energy savings. Who is right in this debate? Should web designers also consider potential energy savings when choosing colors for their sites?"