I absolutely would find that useful. Thank you. In a related query, there is a Settings option that lists subscribed threads. It seems to me that a similar option for subscribed forums should exist too.
There's another approach I use on another message board. On their setup screen, the user is presented with a list of all the forums, and they select which they want to display. I guess it's similar to a subscription. Any new forum the mods add gets displayed automatically, and the user can then choose to deselect if they wish. This way the default new post requests only gets those from the selected forums.