Computer monitors use more energy to display white pixels than black. Other colours use varying amounts of energy between the limits of black and white. This is the theory proposed by Blackle (www.blackle.com), who have come up with a black search engine. It's a front-end to Google, but with a black background, hence the name. Heap Media, the company behind Blackle claim that by making Google searches using a black background, Internet users could collectively save thousands of kilowatt hours in electricity. According to EnergyStar, a typical monitor displaying a full screen of solid colour might use the following amount of ...