Alexis Madrigal for The Atlantic:

Imagine you’ve got a shiny computer that is identical to a Macbook Air, except that it has the energy efficiency of a machine from 20 years ago. That computer would use so much power that you’d get a mere 2.5 seconds of battery life out of the Air’s 50 watt-hour battery instead of the seven hours that the Air actually gets. That is to say, you’d need 10,000 Air batteries to run our hypothetical machine for seven hours. There’s no way you’d fit a beast like that into a slim mailing envelope.

I couldn’t resist quoting the same paragraph Gruber did because this is quite the thing to consider. I remember seeing one of the first PowerBooks (passive matrix grayscale LCD, trackball, huge, tiny battery life) and thinking how amazing it was.

If you had shown 12-year-old me the MacBook Air I use every day now, that boy would have thought it was something out of Star Trek.

Maybe it is.