A mailing list is a list of email addresses that get one and the same message simultaneously. When you send an e-mail message to the mailing list address, it will be forwarded to all the addresses on that mailing list automatically, but none of the receivers will know who the rest of the recipients are. Generally, people have to sign up for a mailing list, but sometimes email addresses are included manually without the approval of their owners. Based on the particular list management software, you may also be able to add new mailing list subscribers, so people will not be able to sign up for your mailing list unless you approve their signup request. The mailing list feature is very valuable in case you’d like to send newsletters on a regular basis or some other kind of periodic announcements to clients, as you’ll need to send one single e-mail message and all the mailing list subscribers will receive it immediately. This way, you won’t need to type in a huge number of email addresses manually.