Spam hurts the earth?

According to a study released by McAfee, “Carbon Footprint of Spam,” the world expends 33 billion kilowatt-hours (KWh) of electricity to send, route, and filter spam messages. That’s the equivalent of the electricity required to power 2.4 million homes, the study estimates. And that much energy use emits the same amount of greenhouse gases as 3.1 million passenger cars using 2 billion gallons of gas.

An Information Week article by Thomas Claburn (Apr 16), "Spam is killing the planet", reminds people that even unnecessary computer use causes pollution.

"... the argument that spam should be fought to save the planet can be applied to other computing activities. Consider the environmental impact of more than 11 million World of Warcraft subscribers, or the broader population of gamers and their consoles. How much energy is frittered away as a result of Facebook, MySpace, and other social networks?"

I must confess that I have procrastinated in replacing a power supply in my older computer. So I've had to leave it running 24x7. This reminder should prod me to get that done this weekend. So how serious are we, really, about being good stewards of God's earth? What can you do this week to reduce your computing carbon footprint?