@scottjenson for sure! I mean that when I'm writing a post, I have control over the audience. IIUC, that's a kind of control over the group of people who might see it in their timeline. It is open-ended, so for example if I shared something with followers, and then I got a new follower later, I could expect they could see it.

OTOH, a message I addressed to a specific user feels more like I'm saying this is for that user only and forever. If that message were encrypted, then it would also be private, as I could expect that even a server admin couldn't read it.

(nb: I've made a bunch of assumptions based on how I think the system works, so some of my points may be due to a flawed mental model!)

@scottjenson I'm a fan of prioritizing the DM experience first.

wrt encryption, part of the challenge is how to interpret "private." Instead of the, "Who can see this?" default posture of Mastodon, this starts to ask something like, "Who cannot see this (beyond the addressed person/people)?"