We are looking at implementing memcached on our system because our server load is too high. The success stories are very compelling. Here’s what I’ve found so far:
vBulletin: Memcache Pooling & Automatic Failover
vBulletin Forums: Memcached How To (thread)
Performance Tuning MySQL (ProfitPapers)
Useful MySQL Stuff including graphing
Server Optimization Forum at vBulletin
MySQL Notes & Tips
How to Setup Memcached
Memcached [...]

On my web server, I believe we use BIND for DNS name resolution. It’s a dedicated server, but we’ve had plenty of problems with DNS resolving. It was very hard to find information on the topic with Google, so I’m going to list my resources here for easy access, and hopefully to help someone else [...]