When you log in to a service with Facebook, the company exposes an enormous amount of sensitive personal information to the service's operator -- everything from your political views to your relationship status. What's more, logging into a service with Facebook also exposes your contacts' personal information to the service: their locations, political views, organizations, religion, and more.
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.