Google Israel went black on Thursday to celebrate Earth Hour and today in the United States, Google has gone black here in a global effort to remind cities and people to turn off their lights for one hour and spread the awareness of energy conservation.
The Google Black concept was first started to try and convince Google that going black will save energy across the world (black vs. white Google homepage).
Last year Google went black in San Francisco to raise awareness for the Lights Out San Francisco campaign.
Google does have the positiion that blackening the Google screen does not save power, but they have done so to boost awareness of energy conservation. So, even though Google has gone black, it looks like they will go back to their traditional homepage tomorrow.
Google cited a study and their positioning on blackening Google last year :
One idea, suggested by the site called “Blackle” (which is not related to Google, by the way, though the site does use our custom search engine), is to reduce energy used by monitors by providing search with a black background. We applaud the spirit of the idea, but our own analysis as well as that of others shows that making the Google homepage black will not reduce energy consumption. To the contrary, on flat-panel monitors (already estimated to be 75% of the market), displaying black may actually increase energy usage. Detailed results from a new study confirm this.
If you want Google Black all of the time, try Blackle, which uses the Google Custom Search Engine service to serve Google resutls on a black screen.