Sounds like Google wave. imho that got complicated really fast (from an end user perspective) when trying to do that.
Do you mean that “reply as PM” (whether it was a group or 1-on-1 PM) was how Google wave worked? I guess I do vaguely remember something like that in the demo so many years ago.
yeah, but it did more than just 1-on-1. You could have entire hidden conversations.
The best use case I found for it was to have two people duke it out a topic as a sort of side-chain that would eventually be made available to the larger group’s thread. It kept the context and allowed them to recontribute the results back to the main document. I can’t imagine it being very useful considering that discourse threads are not community editable like wave had been.
I do like the idea of having semi private topics among sets of people, but not inline. Maybe when you ‘reply as new topic’ it would give the option to list off people to share with (perhaps leveraging how google+ does it?)