As mentioned in my notes below we plan on open-sourcing everything and working towards that goal. For now, you can always simply deploy your build directory if you're working alone, but if you need something that automatically regenerates the site based upon other users edited the CMS, than right now our hosted platform is the only way to go (for now).
One question: can I deploy to my own server (for free) or only through your hosted service? It wasn't clear from the documentation I read online.