[Cosi1125]

Little would prevent attacks by APTs and other powerful groups. (This, btw., is one of the few facets of this problem that technology could help solve.) But a trivial change: a hard requirement to sign up (=send a human-composed message to one of the moderators) to be able to participate (or, in extreme cases, to read the contents) "automagically" stops almost all spam, scrapers (in the extreme case), vandalism, etc. (from my personal experience based on a rather large sample).

I think it's one of the multi-faceted problems where technology (a "moat", "palisade", etc. for your "tribe") should accompany social changes.