What about something like this: https://www.dropbox.com/s/wisoy2og4rb4zps/rationalmedium.pdf [mockup]

Key features:

- Different claims are made, and you can discuss them individually (ie. in a separate thread). This thread would have a summary of the key points at the top, so new users can more easily join the conversation.

- There's an open thread.

- There's a thread to discuss tangents.