Mailing lists (also called ListServs) are electronic discussions about specific topics carried on via email. Mailing list members converse with each other by sending messages to a central server which distributes the message as email to every member of the mailing list. Most mailing lists are open to everyone, although some have membership restrictions. Moderated mailing lists have a list manager who is responsible for ensuring that all messages are appropriate to the topic and purpose of the list.