Links on scalability

This post is simply a collection of articles i particularly liked on scalabilty:

Scalability Best practices: Lessons From Ebay
ChasingSparks: Sharding with Cookie-Based Sessions
The Hitchhikers Guide to PHP Load Balancing - Port:EightyEight
The fav.or.it Blog » Fixing Twitter
Hueniverse: Scaling a Microblogging Service - Part I

update

i started this blog at blog.whythelongroads.com and ported the few posts there and their comments to here. that blog will be going down in the short future.