And a number of negative ones. If someone could data-mine your "true opinions", group-think and mob-mentality becomes a much bigger issue.

Also, either extreme is primed for a big disruptive phase-change if some new technology comes along that makes it easier to conceal or uncover things.

I imagine a post-privacy society is one where people necessarily either are much more tolerant of disparate opinions, or clump together more to like-minded people in enclaves of homogeneity. Possibly a little of both.

To some degree, privacy is important because people judge bases on social norms. If that is lessened, so it the benefit of privacy (not necessarily to the same degree).