You know the pin symbols or when it says track? Well, if you click on that you can keep track of a person's journal when they post a new entry or you can track a specific post and you'll get notified by email. So the people who I like knowing when they post or if I wanna keep track of comments in an interesting discussion, it'll go to my email instead of me combing through my flist (which is very large and I always miss stuff).