This is excellent, and doesn't appear to be too difficult.
1. What is the difference between setting the user_notify field to 0/1 vs. adding a record to the forum_watched table?
2. Can records be simply inserted into forum_watched and then filled in with forum_id, user_id, user_notify to set subscriptions or are there index problems / other tables that need modifying?
3. Is there documentation that would answer my two questions above?