On the Mastodon & Pleroma side, I'd prefer it if every site updated their software to say something like "scope limited posts" instead of "direct messages". The problem is that people misunderstand and put all sorts of private information in those posts, unaware that a server admin (of any server in the conversation) could potentially see that content, just like any other post.

In reality, no admin does this, but they could. And they can do likewise for Twitter and Facebook "DMs".

End to end encryption (E2EE) is so important to privacy that I believe we should avoid giving people the impression that unencrypted communications are private. This is not an endorsement of Twitter's rumored E2EE DMs. Just an acknowledgement that people have sent me contact info, bank information, and even family photos via "direct messages".