There are two kinds of mailing lists, public and private. Anyone can get on the list by sending a subscribe message. Some IEEE newsletters are now being distributed electronically in this manner. Using this system, the IEEE can also distribute conference announcements and tables of contents of publications. Messages are archived in case you are missing some.
Private lists enable groups of IEEE volunteers to receive messages from one source.
Individuals cannot subscribe to get on these lists. Messages sent to any of these lists by members or others not on the list will be discarded. Messages are not archived. If you ask for a private list, you will be able to create and edit the list of recipients, and you will send all messages to those recipients. For example, perhaps you want to circulate a newsletter only to members of your group.