From Seo Wiki - Search Engine Optimization and Programming Languages
Nevow (pronounced like the French nouveau) is a Python web application framework. Template substitution is achieved via a small Tag Attribute Language which is usually embedded in on-disk XML templates, though there is also a pure-Python domain-specific language called Stan, for expressing this markup programmatically. Nevow integrates well with Twisted, a framework for event-driven programming.
Nevow is well-tested (over 700 unit tests as of September 2007) and is deployed on several high-profile web sites, most notably the official Python site, python.org.