Communities are by nature socially centralized. Therefore the right design in my opinion is to have its content bound to pubkeys rather than server addresses. The data can still be redundant if community members take care about archival and hosting. For public communities - like opensource development - this is definitely the way and the data should be widely replicated. This is a key property of #communikeys. My humble opinion about privacy is: if you need personally, generate a new pubkey for the kind of interaction you want to be hiding.