It would be helpful if a question could be marked so that you get a notification when there is new activity. Just something like the red notification you get when a comment gets a response.
It's not perfect; the system could be made to bring more attention via inbox notifications, but it does alert you to activity on your Favorites.
Clicking through to your profile, you'll see badge notifications on each area of activity. In this case, there has been two actions on a favorited question of mine.
What you're asking for is pretty much implemented by the new SE-wide feature of being able to "follow" posts as well as bookmark them:
If you've clicked "follow" on a post, then you will get a little red inbox notification for every new interaction (comment, edit, etc.) on the post.