The "favourite question" system is useful for marking questions that you want to go back to, or what to keep track of changes to. However, it's not simple to see what's changed - you need to look at the activity feed in your profile.
It would be convenient to have an RSS feed (like there is for nearly everything else) that summarised your favourites. Obviously this wouldn't be just questions (since you've seen the question when you favourite it), but answers as well.