Oh, yes - I certainly agree that St4k is a lot faster than Stack Overflow, but I'm not sure quite whether to attribute that to exactly what's happening on the server (remember that the real SO will have load several orders of magnitude greater), fewer 'requirements' (e.g. no analytics?), more efficient markup, or specifically loading markup via AJAX+JSON rather than the 'normal' web route.

I'm surprised there's such (15/1) a difference between the HTML and JSON versions of the same data. Both add their own syntactic cruft, but I wouldn't expect the weight of the markup to be that much greater than the equivalent JSON, unless it's being implemented horribly inefficiently (e.g. very verbose class names, inline styling, DIVitis). I'm suspicious about that 15/1 figure.

All in all, though, this is an interesting approach. Nothing radically new, but definitely good to see a solid proof of concept that we can all relate to. I particularly like the way this gets around any api throttling limits since the St4k server isn't doing the communication with SO, it's all happening client->server, much as if one were just browsing SO as normal. Is there a term for this? It's not quite a proxy, since it's not 'in the middle', but more 'off to the side, not interfering directly, merely offering helpful advice' :)