@doctorclaros Not one that should be relied on, no!

When I write a post, I can choose "Public," "Unlisted," "Followers-Only," "Circle," or "Direct." In that last case, only the people I tag within the post should see it. BUT your server admins can also see it, and it's transmitted in cleartext over the ActivityPub flow, so it's not really private. It's more of a "don't put this on the timeline" feature than a private communication feature.