By having accessible/real time metrics for household power consumption consumers can make real attempts at saving power. Much like the MPG meters in newer vehicle:

Trying to use as little fuel as you can, by driving more smoothly and being a little less heavy on the accelerator, can even become a game of sorts. Nissan, a Japanese carmaker, has calculated that fuel-efficiency gauges can reduce fuel consumption by an average of 10%, so it has decided to put them in all its cars.

Similar effects would be seen in the home.

After you have set up the device you get the first shock: why is the house using so much electricity? Walking around and switching things off soon reveals where savings can be made: lights left on during the day, a television the children are not watching and a surprising number of power supplies keeping themselves warm while the things they are connected to are in “standby” mode.

Economist: Power Plays

Google’s efforts take it one (crucial) step further. By aggregating this data in the cloud and presenting it in a friendly manner, consumer’s can’t help but be curious. Hopefully this curiosity leads to a more energy conscious mentality, even if it is just a game.

This is a huge opportunity for Google. I’m curious how they plan to incorporate/monetize this data.

And further down the list:
This is too funny to make up.