[Chathamization]

That might be somewhat useful, but the thing is after a few hours your conversation with the other person is going to be no better than a private message (since no one else is going to see the topic). Web forums bump the topic back to the top, but that kind of defeats the purpose of the "news" angle. It might be interesting separating the two - have the submissions act like they do know, but have the comments for the submissions be in individual threads in a separate discussion forum.