"By some estimates, the internet now uses 2% of the world's electricity"

I'm not even sure what that means but it sounds deeply scary when linked to the usual tech industries exponential growth. It feels like we're only a few doubling periods away from mankind devoting all it's remaining resources towards maintaining the computronium. But then we're still a long way from constructing nested Matrioshka shells to capture and completely use all the sun's energy output. 

http://www.theguardian.com/sustainable-business/internet-sustainability-renewable-power
http://en.wikipedia.org/wiki/Matrioshka_brain
http://en.wikipedia.org/wiki/Accelerando