Blogroll for tag optimization
eAccelerator - A PHP accelerator, optimizer, and dynamic content cache
How-To Minimize Load Time for Fast User Experiences (UX Booth)
Twitter, an Evolving Architecture (InfoQ)
Smart Clients: ReverseHTTP & WebSockets (igvita.com)
Web Performance Best Practices (Web Speed)
The C10K problem - How to scale web server to serve 10000K clients
Tuning LAMP systems, Part 1: Understanding the LAMP architecture
Tuning LAMP systems, Part 2: Optimizing Apache and PHP
Tuning LAMP systems, Part 3: Tuning your MySQL server
MySQL 5 Optimization and Tuning Guide