What is "design fiction?"

I've been writing "design fiction" for years (see, for example, Knights of the Rainbow Table), and when people ask me to explain it, I say something like, "An engineer might make a prototype to give you a sense of how something works; an architect will do a fly-through to give you a sense of its spatial properties; fiction writers produce design fiction to give you a sense of how a technology might feel." (more…)