1. A way for your list to either: (1) automatically relist into your followers' feeds; or (2) notify your followers, when you add a new list item to it
  2. Because sometimes you miss something huge.
  3. Because sometimes lists are meant to be an ongoing project.
  4. I've made some VERY important additions to several of my lists that no one will ever know about. The world is a cruel, cruel place.
  5. ;)