@david415@moxie The argument that decentralized/federated systems don't necessarily improve privacy when communications partners leak your meta data is sound. However, the control argument is bogus, and as mentioned availability goes beyond technical reachability of a single server.
@david415@moxie More specifically, I agree with @moxie that privacy is neither inherently better nor worse in federated systems - it all depends on the protocol design and where data is stored/handled on a systems level. Centralized systems _can_ protect meta data as well. It's just very hard.