A mailing list is a collection of email addresses that receive the very same message simultaneously. When you send a message to the mailing list address, it will be re-sent to all the addresses on that list automatically, but none of the receivers will learn who the other recipients are. In the general case, one has to join a list, but occasionally email addresses are added manually without the permission of their owners. Depending on the specific mailing list management software, you may also be able to include new mailing list subscribers, so users will not be able to register for a mailing list unless you approve their request. The mailing list feature is quite handy if you want to send newsletters on a regular basis or some other kind of regular announcements to clients, considering that you’ll need to send a single e-mail and all the subscribers will receive it instantaneously. This way, you won’t have to write multiple email addresses manually.