The Big Sibling/Little Sibling List is a way for Big Sibs to keep track of who else is a Big Sib and who and how numerous their Little Sibs are. What is Big Sibs/Little Sibs for? Quoting biophys_kim, "It's so new members can interact with some of the members who have been here a while and are able to ask questions and start to make new friends within the group. It's to seem more welcoming." The original list is located here, where it is sadly defunct.