sorry writing while eating lunch earlier so no doubt could be phrased better :) What I was trying to get at was that there are lots of "optional extras" that s

sorry writing while eating lunch earlier so no doubt could be phrased better :) What I was trying to get at was that there are lots of "optional extras" that seem to get loaded up front at the moment that would be better if they were progressively loaded. I think you see that a lot with SPAs in a way that you didn't when JS was used to 'progressively enhance' sites rather than for all interactions. I don't think it's a problem of SPAs by definition — you could engineer an SPA to progressively load what's needed, and make the first load very slimline & then only load additional features while idle or on request, which is why I think GMail is a bad example. For example, I've just tried logging into Gmail in a fresh Firefox window (no cache) that I set to throttle to a "regular 3G" connection speed in the browser. It took literally 30s to load (with one email in the inbox).