A mailing list is simply a list of addresses to which the same information is being sent. If you were a magazine publisher, you would have a list of the mailing addresses of all the subscribers to the magazine. In the case of an electronic mailing list, we use a list of email addresses from people interested in hearing about or discussing a given topic.
Two common types of email mailing lists are announcement lists and discussion lists.
Announcement lists are are used so that one person or group can send announcements to a group of people, much like a magazine publisher's mailing list is used to send out magazines. For example, a band may use a mailing list to let their fan base know about their upcoming concerts.
A discussion list is used to allow a group of people to discuss topics amongst themselves, with everyone able to send mail to the list and have it distributed to everyone in the group. This discussion may also be moderated, so only selected posts are sent on to the group as a whole, or only certain people are allowed to send to the group. For example, a group of model plane enthusiasts might use a mailing list to share tips about model construction and flying.
Some common terms: