The interfaces shown here at those links above, are real installations from cPanel interface af this server.
This Mailinglist feature is preinstalled and totally configurable by using only CLIENT side admin interfaces.

Administrator will have the ability to post a message from his client, for example Outlook Espress as a normal email message to the following address : userstcp.c-php.com
This message will be re-posted immediately to all the members that have subscribed the list User
All that in the same format that the administrator has assembled it in his CLIENT (Outlook Express)

By a normal installation of this feature all the subscribers will have the ability to post everyoneelse of that list in the same way, while this installation is configured for Read Only Users :-)
In particular in this case admin's account sets which user can mail-list everyonelse ...but admin self cannot mail all subscribers,,, in other words if admin wants to mail-list, Admin must subscribe the list as all others (as a common subscriber) and must priviledge his subscription for posting.
As last there is to say that all that works as a subdomain and files are generated on the fly, they are not existing on the server, it means that of this link http://tcp.c-php.com/mailman/listinfo/users_tcp.c-php.com for example, you would find on this server no mailman or listinfo directory nor users_tcp.c-php.com with whatever index-file.

phpMAILER is of course SOMETHING ELSE   Links & Overview

cPanel Mailinglist is a pre-installed suite on the web server and written in Python Programming Language
What is a Mailing List ? - A mailing list is simply a collection of e-mail addresses that will be receiving mail on a particular topic. Every mailing list has a list name and a list address.
Mailman is actually a Mail List Manager (MLM). The mail list manager is a program on the server that makes it easy to create and remove lists, to add or remove users from lists, and to do things such as make message digests or maintain message archives. As a list subscriber you will only be using the mailing list manager to modify your personal account preferences. Joining or being added to a list is called subscribing. When you leave a list it is called unsubscribing.
Mailman list manager can store a copy of list traffic on the web server that you will be able to access with your browser. Sometimes mail lists will produce a lot of traffic and the additional traffic can be a nuisance in your mailbox. One of the options that you will be able to set allows for the delivery of a digest. If you select by subscribing digest delivery, then Mailman will store all of the messages that the list receives and send them to you bundled together as one large message every day.

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A Mailing List is a list of addresses that receive email when a message is sent to the list address. This allows you to send out messages to everyone on the list such as a monthly newsletter. You can configure many different options when creating a mailing list and it is important to review all possible options.
Common Options : By default, members of a mailing list are able to send messages to that list. If you wish to use the list for distribution only, change the option in Privacy Options -> Sender filters to enable moderation for new list member postings. Then, set the action to take to Discard.
Use the Privacy Options -> Subscription Rules section to configure privacy options for the list. Here you can change who can see the list, who can see the list's members and more.
To add or remove a large number (or a file full of) email addresses, Use the Membership Management -> Mass Subscription and Membership Management -> Mass Removal options.