uhh yeah I just got an email about a reply to a watched thread. That hasn't happened since the forum software switch/update/site change/whatever it was awhile back. Looked and sure enough, email notification of watched threads was turned on. So I turned it back off.
So how did it get turned on?
Yea, yea, yea, that was me. I can change it back, but I need to reevaluate. We are prepping the site for the new modules. Stay tuned.
there is your answer