You may have seen or been to a Google owned website named Blackle. http://www.blackle.com/ This website is the opposite of Google, color wise. Blackle is not bright white, but a midnight black. This website has claimed to save energy by not using as many watts by displaying black instead of white. Other sources claim the opposite.
Sources say that Blackle does NOT work if you have an LCD monitor. In fact, it does the opposite! With LCD monitors, Blackle actually causes you to LOSE one watt hour. The only way Blackle works is if you are using a non LCD monitor.