Awesome Article/Review.

This the first reference I've heard to scales of economy and "Blast Radius" concerns (I.E. How much damage occurs if a data center goes down - apparently Amazon feels that at around 80,000 (or so) servers, it makes more sense to build new data centers, than to make existing ones bigger.

This is why Availability zones have multiple data centers (as many as 6 (10?) in US-East)

Also, while I was aware that Amazon was looking at building their own network stack - I wasn't aware that they'd replaced all their Cisco/Juniper gear with white-label ODMs with their own custom software stack. Now that's a company that takes networking seriously.