This is the review I posted to Amazon on the book Scalability Rules:
Get this book if you're transitioning to the services world or want to improve your skillset without having to make all the mistakes yourself.
The proposal of this book is to present the topics briefly. Once you read these rules, take them to your heart and, from there, learn how to apply it specifically in your environment. It will probably involve doing a lot more reading and experimenting, but at least this book will give you the starting points.
If you have some experience developing and operating a world class service, then you will quickly notice that the authors do know what they're talking about. I've had this experience as a service developer and operator and can definitely relate to most of these lessons.
Also these lessons do not apply only to web sites, but to any web services; and it's beyond scalability, it's about the mind shift to the services world. Developers that did not work on services tend to think they are relatively similar to product - and they are NOT. Companies transitioning from a product to a services focus should buy several copies of this book and give one to each developer, because you can get most of these rules if they are taken into account from day one, not as an afterthought.