Greener Programming

While reading up on jscript performance optimizations today, I happened across an interesting term @ learningtheworld: "Green Programming." Now, I've heard about energy efficient datacenters, servers, etc., but I don't think I've ever heard of green programming. It's an interesting concept, as I'm sure inefficient programming does cause a non trivial amount of power usage. One more trick to guilt the lazy programmers into writing better code! ;)