(Thanks to Jenny for this)
I feel like most of us use a Google search bar in our browsers, but:
When your computer screen is white, an empty Word page, or the Google page, consumes 74 watts, whereas when it’s black it consumes only 59 watts. Mark Ontkush wrote an article about the energy saving that would be achieved if Google had a black screen. Taking into account the huge number of page views, according to his calculations, 750 megawatts/hour per year would be saved.
In a response to this article Google created a black version of its search engine, called Blackle, with the exact same functions as the white version, but with a lower energy consumption at http://www.blackle.com Right on.