This doesn't make sense. Email is a protocol, not a UI. It would be fairly easy to make a UI that displays email like Reddit threads (the hardest part is probably stripping quoted replies). Thunderbird can display the discussion tree, but doesn't inline the message content. GMail inlines message content but linearizes the thread. I am not aware of any clients that inline the discussion content in a tree view.
This doesn't make sense. Email is a protocol, not a UI. It would be fairly easy to make a UI that displays email like Reddit threads (the hardest part is probably stripping quoted replies). Thunderbird can display the discussion tree, but doesn't inline the message content. GMail inlines message content but linearizes the thread. I am not aware of any clients that inline the discussion content in a tree view.