All this tablet sleuthery makes me think about my GNU Social usage.  I'm pretty transparent about a lot of things and I consider whatever I post here to be completely public.  Sometimes I wonder if I overshare but other times I just don't really care enough.  My primary concern in privacy is keeping the advertising barrage away from me (or misleading it as much as possible).  Secondary concern is potential non-state attackers.  Using my real name on a lot of things probably doesn't help much but a pseudonym is just security through obscurity.  It's difficult to get this sort of thing right.