in reply to monk notification feature ...

Yes that already exists (as mentioned).

It'd be useful to expand the scope of this a bit in order to have an ability for a monk to toggle on/off a thread so he could be notified about new posts to threads he didn't originate.

For instance, at any given time I'm trying to follow several threads and often it's cumbersome to manually check each one. Much simpler to get a /msg

Does this appeal to anyone else?