It uses ajax for the order book, but it uses websockets for the ticker and for tracking your own open orders (those pnotify messages for example are in response to websocket events).

I subscribed to the depth.pair channels also (with much hope!), but the orderbook it gives is incorrect.  It does appear to be related to the real order book, but I think (at a guess) it might be missing order replace and order cancel events.  (Curiously though, I think it might be leaking some hidden order data)

Anyway, I live in hope for the new api they're promising