Hidden in the tooltip for today's XKCD, a piece of important existential philosophy:
A human is a system for converting dust billions of years ago into dust billions of years from now via a roundabout process which involves checking email a lot.
I write books. My latest is a YA science fiction novel called Homeland (it's the sequel to Little Brother). More books: Rapture of the Nerds (a novel, with Charlie Stross); With a Little Help (short stories); and The Great Big Beautiful Tomorrow (novella and nonfic). I speak all over the place and I tweet and tumble, too.