Art of scalability - Scalability principles
Good introduction or refresher for people having to deal with scalability issues or architecting some services that will need to be scalable. See the series at hfadeel.com. Couple this series with his Performance Anti-Patterns post and you'll get a good overview.
Comment: those posts are just scratching the surface of scalability, and is missing for people starting to deal with scalability a list of good resources providing more specific details and information. I guess I could do something here...
