I was at Amazon during early development and watched several of the PoA talks about it. On the one hand, the concept is surprisingly simple, on the other hand,

I was at Amazon during early development and watched several of the PoA talks about it. On the one hand, the concept is surprisingly simple, on the other hand, it's such a useful general purpose concept that it's surprising it wasn't done earlier. I believe it's first public use case was Database Migration Service. It's neat to see it offered as it's own product.