"Blackle was created by Heap Media to remind us all of the need to take small steps in our everyday lives to save energy. Blackle searches are powered by Google Custom Search.
Blackle saves energy because the screen is predominantly black. "Image displayed is primarily a function of the user's color settings and desktop graphics, as well as the color and size of open application windows; a given monitor requires more power to display a white (or light) screen than a black (or dark) screen." Roberson et al, 2002
In January 2007 a blog post titled Black Google Would Save 750 Megawatt-hours a Year proposed the theory that a black version of the Google search engine would save a fair bit of energy due to the popularity of the search engine. Since then there has been skepticism about the significance of the energy savings that can be achieved and the cost in terms of readability of black web pages.
We believe that there is value in the concept because even if the energy savings are small, they all add up. Secondly we feel that seeing Blackle every time we load our web browser reminds us that we need to keep taking small steps to save energy."
- 'about blackle'
now seriously, how easy is that?