@riking: I didn’t think of the complexities that would imply by letting people update their posts.
I think if the philosophy is to have a “flat tree”, then all replies to the original post should link to very first post id.
SettingIn-Reply-To to the last post made will make the email client display the conversation as a tree with as many levels as posts are in the thread.
So I guess implementing the changes I suggest in
thank you guys