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.