I've always been an “every little bit counts” kind of guy. For me, saving a glass or a bucket of water is just as important as raising the water level in Angat Dam. So blackle.com makes sense. And while the amount of energy expended while using a white screen is negligible, multiplying it by the number of google hits may just prove it significant. In any case, every little bit helps.
Save energy. Google with a black screen.