WhatWhyHowZServer
What is ZServer? essentially ZServer is Sam Rushings medusa server with some modifications to serve out of the ZODB instead of the local filesystem. What is Medusa? From Medusa's homepage it is described, "A high-performance extensible single-threaded server architecture (currently supporting HTTP, FTP, and other Internet protocols) for Unix and Windows."
Why? well, its been used in Production systems for years, there are some people in the Python community that understand it thoroughly and its free!