An older piece from FoundationDB (archived by odbms.org) that talks about the same issues and comes to many of the same conclusions: http://www.odbms.org/wp-content/uploads/2013/11/cap-theorem....

I think the overloaded term "availability" has been a big source of confusion for many trying to understand the implications of the CAP theorem at a simple level.

For example, a simple PAXOS implementation is "high availability" (continues working even when individual machines fail) but sacrifices "availability" in the CAP sense.