I would think an impure fixie would be either rides other bikes or rides with a brake and possibly a flip flop hub? Or, most likely, by ease of use the keyboard has encouraged the poster to type extra words that aren't required, I find myself doing that quite often and being misunderstood, heh.

I stopped riding fixed all the time and now go single speed (with two brakes of course). I forgot how much fun coasting is, and what a nice reward for climbing a hill!