Most techno-geeks know about Moore's Law, the long-term computing trend whereby the number of transistors that can be affordably placed on an integrated circuit doubles approximately every 18 months or so. Other technology innovations have followed similar trajectories, including computer processing speed, memory capacity, and sensors -- even the number and size of pixels in digital cameras.

Now, add to that the electrical efficiency of computing -- that is, the number of computations that can be completed per kilowatt-hour of electricity. That's according to Jonathan Koomey, a professor at Stanford and an entrepreneur whose work spans climate solutions, critical thinking skills and the energy and environmental effects of information technology. Koomey's new book was published last week, and GreenBiz.com's Matthew Wheeland took the occasion to ask him about the opportunities for entrepreneurs to address the climate crisis. Definitely worth a read.

Of course, the intersection of sustainability and innovation is at the heart of our editorial mission, and this week's crop of stories is a case in point: greener freezer technology being introduced by Ben & Jerry's and Unilever ... the latest in a series from the Rocky Mountain Institute, this week on the trillion-dollar opportunities to be found in building energy efficiency ... and Paul Baier's look at four innovative startups that are lowering the costs of commercial energy audits.

And while we're on the topic, check out this week's featured One Great Idea video: Matt Rogers, founder and engineering czar at Nest Labs, on how good design can move consumers to change their home energy habits.