[rdtsc]

> Usually you end up having to store the entire version history, which Cassandra supports by clustering with uuids."

You need the history to be able to reduce the entropy by solving and eliminating conflicts, unless CRDTs are used (which I think Riak supports CRDT counters). Otherwise merging is custom to an application. Merging two {X,Y} position updates is not the same as merging two shopping cart updates or the same as merging and address and email tuple. Sounds like Cassandra is just sweeping the problem under the rug.