Could a smiley face convince you to reduce electric consumption?

The smiley face that teachers put on good homework papers is rearing its smiley head in another spot: Utility bills.

Power company customers who use less power get a smiley face, or a few if they're really saving a lot of electricity, from utilities in Sacramento, Seattle and Chicago, according to a New York Times story. The Sacramento Municipal Utility District was putting frowny faces on statements of its worst customers, but stopped after complaints.

Along with the smiley faces for energy savers, the utility statements compare the customer's power usage with their neighbors, showing how little electricity 20 of their "green" neighbors are using and what 100 homes of similar size in their neighborhood are using. It's the latest move to try to inspire you to keep up (or down) with the neighbors.

The Sacramento utility found in an assessing the program after six months that customers who received the personalized report reduced energy use by 2% or more than those who got standard statements.