A mailing list is a collection of email addresses, and the purpose of it is to send material to a group of recipients. Generally speaking, there are two different types, announcement list and discussion list.
Announcement lists are one-way broadcasting method. Newsletter from organisations or individuals is a perfect example of such category. It generally includes promotions, news update, etc.. And the recipients can only reply to the sender.
Discussion lists, on the other hand, allow all recipients to communicate with each other by emails.
For recipients, an email account is essential for such services. The term subscribe usually is the cue for this service. By inputing you email address,