[derefr]

> I don't want to say "clone" because nobody outside Amazon really knows how S3 works

You can deduce quite a bit about S3's system architecture from the kind of time and consistency guarantees it provides, the optimal and pessimal cases for bucket key naming, etc. Riak CS hits pretty much all those same notes, so I would hazard that you can get a good high-level sense of S3's architecture by looking at Riak's.