Gabriel-
Hm, how does this integrate with caching? I would also vote for switching this feature off by default, especially for anon users (no caching for the biggest pages otherwise).
I don't see how this affects caching on the Squid level. If you set the size threshold to 30K, then a page will be compressed if it has more than this number of characters, but the URL will not show the &collapse=false parameter. Surely this should be treated like any other page?
Instead of re-rendering pages for everyone i think it would make more sense to render the page only once and do the customizations in js/css as far as possible. Hiding sections via js or css for the browsers that support it similar to what we do with the toc currently shouldn't be too hard and would save many round-trips to the server and repeated rendering.
The whole point of collapsing pages is not to have to send 90K to a dialup user whenever they view VfD. I fail to see how this can be achieved using JavaScript.
Regards,
Erik