Ian Bicking: the old part of his blog

Comment

And, don't forget that WebWare users would also be able to switch out 1, 1a, and 1b for something else altogether, like mod_python or PEAK's FastCGI runner, once they support WSGI.

Of course, that's assuming that the other pieces in your stack support a multi-process execution model as well as the single process, multi-thread modes. But even if they don't, the web server can be any single-process multi-thread WSGI server or gateway.
Comment on A WSGI Stack
by Phillip J. Eby