Google PowerMeter

The idea with the Powermeter is that if people knew how much electricity they were using to run individual electric appliances, they’d cut down use.
Google cites figures showing that regularly viewing real-time energy use prods people to cut electricity by 5 percent to 15 percent on average through behavioral changes. That could translate to saving $60 to $180 per year for a U.S. household with an annual average electricity bill of $1,200.

The PowerMeter will work on an iGoogle home page when it becomes available to the public sometime later this year.
According to The New York Times:
Google plans to enhance PowerMeter with “social” tools that will allow users to compare their electricity consumption with that of their neighbors or friends. And it plans to allow third parties to develop their own applications that would enhance its usefulness. A programmer, for instance, could create a tool that normalizes the data for variations in weather.
Even though it’s not ready for prime time, Google is providing info on the product in the hope of interesting potential partners.