A mailing list is a list of email addresses which receive the very same message simultaneously. When you send a message to the mailing list address, it will be re-sent to all the email addresses on that list automatically, but none of the receivers will know who the other recipients are. In the general case, people have to subscribe to a mailing list, but sometimes email addresses are added manually without the permission of their owners. Based on the particular list administration software, you may also be able to add new subscribers, so users cannot subscribe to a mailing list unless you authorize their request. The mailing list functionality is quite useful in case you’d like to send regular newsletters or some other type of periodic notifications to clients, as you will have to send out one single e-mail and all the mailing list subscribers will get it instantly. As a consequence, you will not need to insert a lot of mailboxes manually.