> Because your tornado app runs as a stand-alone HTTP server that is directly coupled to your application classes, you need to run multiple processes to serve multiple requests.

Really? My understanding is that an async http server like Tornado should service many requests with the same process. (This is the case with Twisted and nginx, at least.) It should be a matter of writing your application in the same async, callback-driven style. Or am I misunderstanding something?

"There are changes in the master branch of Tornado on github to make Tornado multi-threaded, spawning a thread per CPU core, but this will not change the scaling concern and will complicate the equation a bit more"

Wrong. It forks.

http://github.com/facebook/tornado/commit/6fb90ae694190fcedc...

A pretty good overview of Tornado. I've been using it as a backend for a real-time web game and from what I've seen so far, its pretty good. I especially like how small and light-weight it is (which kinda lets them get away with non-existent documentation)

Much love for tornado, though I ditched their templating for genshi. It also works pretty good as a Cron sort of engine for polling/scraping.