I thought for sure they did a PJAX [1] like design when I saw the spinner to keep asset loading minimal (why c2 would need that is beyond me).
But it is even worse. A full page reload on each click and then an XMLHTTPRequest call is made for some JSON.
I wonder who is running and why they picked such an awful design. Do people just not know how to write old web 1.0 apps?
For now I will play devils advocate and just assume perhaps they are offering JSON like API so that someone else can maybe write a better skin. If some one does hopefully they will use push state.
EDIT
I clicked around to see what Ward has been up to and now I can sort of see why c2 is the way it is. Basically Ward is working on Federated Wiki. I think the idea is sort of cool as it is yet another attempt to continue to decentralize the web.
I believe it is going to be based on some JSON protocol but it would be interesting and perhaps have greater consumption if it was in Google AMP format or supported that format or converted or whatever (not c2 but the federated wiki stuff).