On Fri, 05 Nov 2010 08:45:27 +0100, Sebastian Spaeth <Sebastian@SSpaeth.de> wrote:
> One UI improvement I would love is to see the number of unread 
> emails in a thread in notmuch-show view. I often reply to a 
> mail in a thread just to see that there are followup mails that 
> resolve the issue already.
> 
> If I had seen that there are more unread mails in that thread 
> (or at least that branch of the thread), I would read those first 
> before hitting reply.
> 
> What do others think?

Does `C-u M-RET' help?