Forgive my saying so, but this is all getting a little nutty. If we're worried about our email addresses becoming discoverable, that ship sailed a long time ago. If we're worried about spam -- well that's not been a huge problem. KMail has a delete function, and I suppose that other mail clients do as well. If we wish to write freely about things that are non-technical, then forming another list in another place, as encrypted as anyone wants, could be done. And having a chat channel, if someone wanted to set it up, might be fun.