The Internet community distributes news by the use of mailing lists. These are lists of subscriber's mailbox addresses and remailing sublists of all intended recipients. These mailing lists operate by remailing a copy of the information to be distributed to each subscriber on the mailing list. Such remailing is inefficient when a mailing list grows beyond a dozen or so people, since sending a separate copy to each of the subscribers occupies large quantities of network bandwidth, CPU resources, and significant amounts of disk storage at the destination host. There is also a significant problem in maintenance of the list itself: as subscribers move from one job to another; as new subscribers join and old ones leave; and as hosts come in and out of service.