Partial page caching
See the RFC at mw.org for current-day information.
Both Varnish and Squid support edge side includes (ESI), although allegedly Varnish's support is limited.
If implemented, Mediawiki could send out sections of a page like so:
<esi:include src="http://en.wikipedia.org/wiki/Special:CentralNotice?action=gimmestuff" onerror="continue"/>
This would be interesting to have as a parser feature, so that dynamic content in a page can be included without invalidating the cache of the entire page. This would let us do lots of cool things like:
- Dynamically changing content based on the user's location
- Instant banner loading for CentralNotice
- Partially cache pages for logged in users to optimize page loading
- SVG client-side rendering
Gabriel Wicke may have experimented with this at one time. Artur Bergman/Wikia has played with it too.