Mailing lists typically come in two flavors:
1. Announcement lists are a collection of email addresses where you send the same content. Using an announcement list provides a great opportunity for sending newsletters, product updates, and targeted information to your member base. These lists are usually setup to push content to the readership without letting them respond. Example: A local retailer sends out a notice for a one day 50% off sale to its preferred customers.
2. Discussion lists allow readers to reply to the entire member base immediately or in a "Digest" format where all recent responses are mailed out periodically. Use of discussion based lists allows for readers to share content, questions, and insights within their member base. Example: A hobby group member that has a question about a car engine uses their discussion list to solicit help.
Typically mailing lists will have a readership that has requested (opted-in) to receive content via email. Members should have the ability to subscribe and unsubscribe themselves through a webpage request form or via email sent to a special email address. This way the list's membership can grow without the need to manage local mailing lists.