Blackle.com

[Zeus_Hunt]

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.

Blackle.com

[Lite]

This only really applies for those using CRT monitors. LCD's use much less power as it is (and grey is the best colour for them to display, although the difference in power consumption between colours isn't great, based on my current knowledge of the technology).

[Zeus_Hunt]

Considering in HP bangalore itself we have around 30k employees with atleast 10k comps in blore itself with atleat 9k CRT monitors

I think these many comps should yield some energy savings.

[Samurai]

To further Lite's response...

This is true only for CRT monitors (which are obsolete now).

Only CRT displays use more energy to display brighter things. On an LCD monitor, a black pixel uses more energy than a white pixel.

For an LCD monitor, the backlight on an LCD is on for the entire LCD, regardless of which color is being shown. An LCD monitor uses subtractive color — a white pixel lets the backlight pass through, and a black pixel is using red green and blue to filter and blockout the backlight. To display a black pixel, the LCD blocks out light. When an LCD monitor shows pure black, that’s actually the point at which the monitor is working the hardest, blocking out lights for all the pixels (thus using more voltage). Changing from black to white may save some energy on CRT displays, it might actually cause LCD displays to use slightly more energy.

That means, if you’re going to use one of these “Black Google” sites using an LCD monitor, you’re actually wasting more energy. Not to mention, that it will cause unnecessary stress to your eyes, possibly leading to computer vision syndrome......

Source: Common Man's Thoughts