Wow. Look at me on the front page of Hacker News!
Our systems are extremely modular. We've previously disclosed that in excess of a hundred discrete services may be called to generate a single page on our web site. You can find more info about that at the following link.
http://highscalability.com/amazon-architecture
When we refer to a deployment at Amazon it means a single code push to one or more servers. For example, if you deploy a new piece of code to a thousand hosts that counts as one deployment. In other words a distinct update is pushed every 11.6 seconds.
Hopefully that makes sense.