Ask HN: Details of Amazon's infrastructure

After reading Steve Yegge's platforms rant and highscalability.com/amazon-architecture, I've become really interested in Amazon's infrastructure.

Unfortunately, unlike Google or Facebook, there seems to be very little information available about Amazon.

So, can (Ex)Amazonians share some interesting facts? I'm interested in just about everything - but especially services. Some specific questions:

- How does service-to-service routing work? Is it just normal TCP/IP or is something more going on?

- What protocols are used for service communication?

- How does service registry handle hierarchical services? I.e. services, that are hidden behind an "interface" service.

Thanks