This screen shows the real name for all the MailMan users, and their group and email address. There are columns showing the number of lists they are subscribed to, and the number of Mailshots they have been sent. By clicking on their name, you can update their preferred name and group code. To remove them from a list, or add them to a new list, you can edit their subscriptions by using the "Edit" link in column Lists.
At the top of the screen is an Add button that allows the registration of a new User. It prompts for the Group code, their name and email:
See also:
04.4 How To: Create a new User
Webmaster Guide: 04.1Joomla Users