I think it'd be interesting to have an option for either type. I find a lot of commentary is suppressed because people don't want other people to see their thou

I think it'd be interesting to have an option for either type. I find a lot of commentary is suppressed because people don't want other people to see their thoughts, whereas with email, they can just reply directly with thoughts. However, I think you're right, that sometimes it's useful to have a group discussion. I'm thinking that would be a link at the bottom of the email that goes to a webapp that allows a more FB-like experience that people can opt-into.