Yeah, if you're an ACID person, this approach is going to present conceptual challenges. The propagation delay is a mostly-solved problem, which I know because

Yeah, if you're an ACID person, this approach is going to present conceptual challenges. The propagation delay is a mostly-solved problem, which I know because lots of high-scale sites work. Getting a summary of their design decisions around this would be a huge time-saver, but I don't know of one.