To study various components of Mailman and the installation of the same package.

Theory:  GNU Mailman is a GNU package for managing electronic mailing lists. It is free software, distributed freely under the GNU General Public License. Mailman’s chief distinction is its easy-to-use web interface for list administration.
Mailman is written in the Python programming language. It can work with any common Unix mail server software, including Postfix,Sendmail and gmail.
The integration with the free mail server software exim (which is used by the Debian GNU/Linux by default) is probably best: Using special configuration rules, exim knows which addresses are used by Mailman and automatically forwards all mails which are handled by Mailman to Mailman, without having to set customized aliases for each individual mailing list, as it is custom with most or all other mail servers.
User features include the Web interface, built-in archiving of messages, automatic processing of bounce messages, digest mode, and spam filtering.
By default, Mailman sends out a reminder message on the first of the month (local time) to all subscribers, causing many netizens to proclaim the first of the month to be “Mailman Day” as the messages start trickling in from all around the globe
 What is a mailing list?
A mailing list is simply a list of addresses to which the same information is being sent. If you were a magazine publisher, you would have a list of the mailing addresses of all the subscribers to the magazine. In the case of an electronic mailing list, we use a list of email addresses from people interested in hearing about or discussing a given topic.
Two common types of email mailing lists are announcement lists and discussion lists.
Announcement lists are used so that one person or group can send announcements to a group of people, much like a magazine publisher’s mailing list is used to send out magazines. For example, a band may use an announcement mailing list to let their fan base know about their upcoming concerts.
A discussion list allows a group of people to discuss topics amongst themselves, with everyone able to send mail to the list and have it distributed to everyone in the group. This discussion may also be moderated, so only selected posts are sent on to the group as a whole, or only certain people are allowed to send to the group. For example, a group of model plane enthusiasts might use a discussion mailing list to share tips about model construction and flying.
Some common terms:

• A “post” typically denotes a message sent to a mailing list. (Think of posting a message on a bulletin board.)
• People who are part of an electronic mailing list are usually called the list’s “members” or “subscribers.”
• “List administrators” are the people in charge of maintaining that one list. Lists may have one or more administrators.
• A list may also have people in charge of reading posts and deciding if they should be sent on to all subscribers. These people are called list moderators.
• Often more than one electronic mailing list will be run using the same piece of software. The person who maintains the software which runs the lists is called the “site administrator.” Often the site administrator also administrates individual lists.