1. The "Receive e-mail notifications for updates to this thread?" checkbox should be present on every new post and full reply box.
2. There should also be a "Receive e-mail notifications for updates to new posts?" check-box in the user's Control Panel settings page.
3. This CP checkbox should be selected by default for new users, unselected for existing users for compatibility.
4. When publishing a new post, the checkbox should pick the default value from the user's CP but let it select or unselect it.
5. A tooltip for this checkbox on new post forms should inform the user that he can set the default behavior in their CP.
6. A flashing "NEW!" information line about this change should appear the first time the user visits their CP or publishes a new post.

i'd do it myself if I knew how!  ^-^