Each list type is configured to support specific kinds of mailing lists and use cases. Kavi® Mailing List Manager provides a set of six default list types such as one designed for for public discussion groups and one designed for newsletters.

For instance, an administrator could create several newsletters based on the 'Newsletter' list type. These newsletters would all have different names and descriptions, but would have certain traits in common from having the same underlying list type configuration. In the newsletter example, the list type is configured so that messages to be posted to that newsletter are accepted from everyone, but are all routed to a moderation queue rather than being posted directly to any of the newsletters. This default list type allows the public to subscribe directly via email subscription requests.

Some configuration options set at the list type level are modified at the list level. Using the newsletter example, imagine a mailing list administrator uses the Add a Mailing List tool to create newsletters aimed at different target audiences. Even though the underlying list type allows anyone to subscribe, the administrator uses the 'List Availability' option from the Add a Mailing List tool to override the default list type configuration, and creates one newsletter that is available to the public, another that is available only to subscribers and another that is available only to administrators.

Here is the easiest way to view list type configuration options if you want to:

Whichever of the preceding paths you took, you will see the same list type configuration options (of course, the option settings will vary). To get a quick grasp of the list type configuration, read each option label and description of the setting. If you don't immediately understand the setting, refer to the page help or click the links in the following sections: List type feature options and List type access control options.

Feature options tend to be intuitive and easy to grasp, whereas access control options are more complex. If you are involved in the more challenging aspects of working with list types—such as adding custom list types or troubleshooting list behavior—you may need to study other help documents that discuss access control in depth, especially List User Levels and Access Control and, if you are working with a moderated list, Moderation.

Each option setting description includes the ezmlm-make arguments that pertain to that setting. This information is included for use by ezmlm experts, but the arguments are also useful for reference purposes, especially when you are dealing with a custom list type rather than the default list types documented here. Some of these arguments are included in the documentation, particularly the -MOU arguments, which work in combination to control who can post to the list. If you want to look up an individual argument in the ezmlm-make argument string, see Ezmlm Quick Reference Guide, but if you want to understand -MOU combinations, you should see the Posting access matrix in the Posting Access Tables document.

There are four access control options available at the list type level. One sets access to archives, two set the subscription process and one determines which kinds of users can post messages directly to a list and what happens to messages from other kinds of users. As above, click the link to see an overview of the option, then read the description for more information and links to related documents.

To understand how list types affect list access and which list types are best suited for which use cases, you must understand the basic principals defined in List User Levels and Access Control.

Lists used to publish information, such as those that would be based on the 'Newsletter' and 'Announce Only' default list types, are configured quite differently than list types designed to support discussion groups. In particular, they control access to posting to protect the quality of list content, since (unlike a discussion group) the information distributed through the list will directly reflect on the organization or subgroup. Posting control measures include list user level restrictions and message moderation. If posting will always be handled by a small group of users, the list might only allow moderators to post, as in the 'Announce Only' default list type. If lists of this type want to be more inclusive about who is allowed to post, they can set the list type to accept public posts but send them for moderation, like the 'Newsletter' default list type.

Now consider the audience. Will lists of this type sometimes be used to publish information to the public? If so, the list type must be configured to allow public subscriptions. When an actual list is created, tighter restrictions based on user level can be imposed. The 'Newsletter' default list type is configured this way, but the 'Announce Only' type is designed to disseminate potentially sensitive information, so it is configured to apply the most highly controlled subscriber access option, the closed setting in the Subscription Model option.

Large discussion forums are more inclusive and public by nature, and less inclined to limit access to post, subscribe or view archives. However, the more open a list is, the more vulnerable it is to abuse and other diseconomies of scale. There are two public default list types, but only Public Discussion Group allows public users to post messages directly. The other default list type, Moderated Public Discussion Group accepts public posts but sends them for moderation. Both accept public subscribe/unsubscribe requests.

Small forums generally serve exclusive groups that may conduct high-level discussions through the list, so there is an expectation of privacy. This kind of discussion group usually restricts the ability to subscribe to the list and then only allows subscribers to post directly. Posts from lower level users are sent for moderation or rejected.

The Moderated Private Discussion Group default list type allows subscribers and higher level users to post directly but sends messages from the public (i.e., from addresses that aren't on any of its subscriber lists) for moderation. Lists of this type are closed to public subscription requests submitted via email, but depending on the configuration at the list level, will be visible through Members pages or Admin pages. Since the list isn't visible to the public, most senders submitting posts from public addresses will be members who are subscribed under other addresses, or staff or others closely associated with the organization who need to distribute messages to the group served by the list. This list type works well for groups that need to be able to receive posts from non-subscribers, but want to prevent spam or other inappropriate content from being posted to the list. Trusted non-subscribers can be given direct posting privileges by being added to the Poster List.

Another type of configuration that serves private discussion groups well is the Closed Private Discussion Group default list type. This type also allows subscribers to post directly, but posts from the public are rejected (i.e. deleted), rather than moderated. Lists of this type can accept posts from senders who aren't on the subscription or moderator lists if they are manually added to the Poster List. Like the other private discussion group list type, it is closed to public subscription requests and only visible through Members pages or Admin pages, depending on the configuration of the individual list.