Users who logged onto Google's search engine in the San Francisco Bay area on Saturday were treated to a black homepage, and it had nothing to do with Halloween.
Google said it turned out the lights on the Google.com homepage to make people aware of Lights Out San Francisco, a citywide conservation event that took place Saturday.
Event organizers asked everyone in the San Francisco area to install one compact fluorescent light bulb and turn off their lights for one hour, from 8:00 p.m. to 9:00 p.m. PDT, on Saturday.
Organizers estimated that turning lights out in San Francisco for even one hour could save as much as 15% of the energy consumed on an average Saturday night.
"Given our company's commitment to environmental awareness and energy efficiency, we strongly support the Lights Out campaign, and ... darkened our homepage [Saturday] to help spread awareness of what we hope will be a highly successful citywide event," Google said in a statement.
Google said it wanted to do its part to help combat climate change and decided to participate in the event. "In short, we really like it. So we did something about it," the company said.
However, Google said while it's committed to combating climate change by promoting efficient energy use, it said permanently changing the color of its homepage to black wouldn't be beneficial to the environment or its users.
"However, we're always on the lookout for ways to improve the user experience, and if new research uncovers new findings, our feelings on the subject could change," the company said.
Australian developer Heap Media, however, disagrees. Heap Media owns and operates search engine Blackle.com that has a black homepage. Heap Media said it created Blackle, which is powered by Google Custom Search, to remind everyone to conserve energy.
Heap Media said Blackle saves energy because the screen is predominantly black, and a monitor requires less energy to display a black or dark screen than it does to display a white or light screen.
Heap Media points to a January blog post from EcoIron that theorized that a black version of the Google search engine would save a significant amount of energy. However, Heap Media acknowledged that since that post appeared there has been skepticism about the significance of the energy savings that could be achieved if Google changes to black.
"We believe that there is value in the concept because even if the energy savings are small, they all add up," Heap Media said on the Blackle site. "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."