@taylorlorenz The challenge with "followers only" is that if you have unrestricted follows, then ... the protection offered is pretty thin. A hostile actor could simply follow your profile.
I've long had mixed feelings on that setting. I'd rather it were restricted to a set of profiles I'd specifically selected myself.
@bhawthorne That's my general use.
In practice, I use it very rarely myself.
@bhawthorne I see people who seem to use it that way.
One thing that really bothers me is that the scope of replies to Followers Only is not the followers of the initial toot, but of the follow-up toot.
For people discussing personal matters and such, whom I know well enough to respond, I'll preferentially reply with a DM (which opens a whole 'nother can of worms), as what I say to them discloses both their conversation and any context visible from my own.
This is where the post/comment format of sites such as Diaspora*, Google+ (RIP), FB, etc., makes more sense: the conversational scope of the entire thread is that of the parent post itself.
I don't recommend Mastodon for anyone requiring robust tradecraft.