A mailing list is a list of email addresses that get one and the same email simultaneously. When you send an e-mail message to the mailing list address, your message will be re-sent to all the email addresses on that list automatically, but none of the receivers will see the other recipients. In the general case, users have to join a mailing list, but sometimes mailboxes are included manually without the permission of their owners. Based on the concrete mailing list management software, you may also be able to add new mailing list subscribers, so people cannot sign up for a mailing list unless you authorize their request. The mailing list option is rather handy if you’d like to send regular newsletters or some other type of periodic announcements to customers, since you’ll have to send only one email and all of the mailing list subscribers will receive it instantaneously. As a result, you won’t need to enter a huge number of mailboxes manually.