The list owner is the person ultimately responsible for deciding the structure and the use of the list. Generally, this will be a person who holds some position of authority within the organization. The focus of the list can be as general or as narrow as you need it to be.
Lists can be either open or restricted.
Open lists are available to anyone in the world. Restricted lists are accessible to only a select group of users that is determined by the list manager. The list manager must manually subscribe each user to restricted lists. Lists can also be unmoderated or moderated. Messages sent to an unmoderated list are posted to the list automatically.