@sandro @cwebber I suggested in that email that a conversation hosted on the Privacy Interest Group (PING) call next week would be one way to go.

I strongly suspect that Mastodon having many users has not meant that all privacy issues are surfaced and resolved. (Indeed, privacy concerns/confusions around the audience of federated toots are common.) But I agree that having an email/teleconference with Mastodon devs and not just ActivityPub could help make it concrete.