Visitor (or user whatever) requests
site.com/page1/ trough GET, then
site.com/page1/ gets cached by the server, and all further requests of that page are served from cache, until a POST request is received.
When a POST request is received, cache gets flushed, page generated normally trough the script, and at the next GET request cache the page again until next POST request and so on...
Does it sound reliable and possible? Is there some Apache module that is able to do this? I think that some shared hosts do this (so they can stuff many sites on a server), but I'm not 100% sure.