What difference does a color make?
As is explained here, in January a blogger noted that white computer screens use slightly more energy than black ones [Update -- only for CRTs, not for flat panels -- see comments].
After a few back o’ the envelope calculations, it was estimated that if the search engine giant Google switched its screen from white to black, 750 megawatt-hours of energy could be saved globally each year.
Fast forward a few months and Google has started a trial of the black-screened search engine – Blackle, found at www.blackle.com. The website also keeps track of how many hours of energy have been saved. When I visited, the number was up to 116,992.364 Watt hours.
Certainly a small, practically mindless, but creative change.