Why use Black Web Pages?

There's been an interesting discussion on Digg about how the color of WebPages affects the amount of power consumed, with the discussion centering on just how much power would be saved if Google switched to an all-black layout. The theory goes that black WebPages use 59 watts of power, 15 watts less than a white webpage does, and calculating that with 200 million queries a day, you get 8.3 Megawatt-hours per day, or 3 gigawatts (Marty!) per year, all of which means Black Google saves $300,000 per year.

Of course, the theory doesn't hold up under more advanced analysis. Turns out that this only really applies to CRT monitors, and with LCDs cheap and popular, and installed in all laptops (which make up over 50% of computers sold every year), the Black Google theory may only be true for a quarter, or less of all computer monitors in the United States . Or, as this guy says:

The US alone generates 4,100,000,000 Megawatt hours per year. 3,000 Megawatt hours amount to about 0.00007% of US energy consumption. Reduce that number by 75% (because it only applies to CRTs), and we're talking about 0.00001% of the US energy generation for a year.

Still, it's a pretty cool idea; at the very least it makes me think about how we can conserve energy by doing little things.