Google - earth hour

Google: "Google users in the United States will notice today that we 'turned the lights out' on the Google.com homepage as a gesture to raise awareness of a worldwide energy conservation effort called Earth Hour. As to why we don't do this permanently - it saves no energy; modern displays use the same amount of power regardless of what they display. However, you can do something to reduce the energy consumption of your home PC by joining the Climate Savers Computing Initiative."