It would be great if phabricator would integrate with reverse caching proxies such as squid, varnish. By doing stuff like setting the appropriate Cache-Control, Expires header. And by sending purge requests to the reverse proxy when pages were modified. Perhaps using Edge Side Includes.
Webapps capable of that are for example mediawiki. Example implementation:
Note, "SquidUpdate" works fine with varnish. You don't need specific implementations of varnish plus and extra one for squid. If this is done once, it's up to the reverse proxies to work with it.
Another webapp capable of this is wordpress's w3 total cache plugin: