I'm also confused. Tornado is definitely a more compelling web framework. Who doesn't want the ability to have tons and tons and tons of long-lived connections?
The article itself says, "While this HOWTO tries to give an overview of Python in the web, it cannot always be as up to date as desired. Web development in Python is rapidly moving forward, so the wiki page on Web Programming [1] may be more in sync with recent development."
So it may not have been the best resource to present on HN in the first place.
Tornado relies on its own HTTP server, but its modules for everything from templating to authentication are loosely coupled, so you can take them or leave them.
To your point, I'd be curious to see a non-Tornado server that is Tornado compatible on the backend. It could be an interesting project. I would counter, however, that any server choice has its own inertia--changing web servers is hardly ever a simple process.
