This allows you to keep up with what people your interested in are saying without having to read EVERY post... there is also an everyone news feed which is better than the whats new... http://xenforo.com/community/members/news-feed
Ok, I was stalking person A, then added person B & C to my stalking list.
But B & C are not showing up in my newsfeed even though they have made many posts, so changes to the list only affect the future?
I am thinking this could be an excellent moderating too. I can sense when someone is about to mis-behave on our forms, if that is the way it works then I could stalk them for a few days and check their posts.