Edge Side Includes. Proxies like Squid and Varnish support it for inclusion of dynamic data in otherwise cache-able pages.

http://www.w3.org/TR/esi-lang

It seems like this would not be mandatory in Tornado, since it is an app server; from my reading I'm assuming all pages are dynamic.

:-)

ESI: http://www.akamai.com/html/support/esi.html

e.g. When you and I log into ff, simplifying greatly, that page would say, "Welcome, Bret" or "Welcome, Prakash". If you could abstract away "Bret" and "Prakash", that page would be cacheable. And, the db hit is only for that particular fragment.

You would need to re-code the pages with esi tags to do it. The other way would be to use javascript to do the same.

What do you think?