web-optimizator - Google Code
http://code.google.com/p/web-optimizator/

This application is aimed to automate all clientside improvements for website that should significantly increase load speed of its pages.

google support for a/b testing etc to optimize web site performance.

Multivariate Testing

Here's what to do: Discover how multivariate testing can increase your profits...then compare software tools using the comparison chart below. Be warned, though: this chart doesn't tell the whole story. Find out the reality of what the software is like, by reading the descriptions and user reviews of it. And, once you've used the software yourself, please come back to submit a review of it.

By http://bit.ly/Tweets2Delicious