The development focus is engaging your users for repeat traffic, hence users interacting with a thread and it being added to their watchlist.
It seems that you could either:
- Find all instances of the mailer class (its named $mailer), and remove those that you don't wish to send mail.
- Edit out the check box for adding posts to watchlists (the ADDTOFAV language string is in both newpost.tpl and newreply.tpl)
