Ace905 writes: "If you're a regular Google Search Engine user, you may notice the site appears drastically different today. Google has changed their home page background to black and now displays the notice, "We've turned the lights out. Now it's your turn". Google is trying to raise awareness of Earth Hour — an annual event where citizens all over the globe turn out their lights for one hour to raise awareness of environmental change.
Google is careful to explain that by darkening their web site, they're not actually saving any electricity — which is an interesting answer to a question I never considered. When I saw the page all dark and black, I thought some sort of cataclysmic event had just occured and this was Googles version of a flag at half-mast. Maybe in a way that's exactly what this is. A better explanation can be found at Google and on the site they ultimately link to."