pop3ml

This is a php script class to manage Mailing lists without a local smtp server. You need only a simple pop3 mail account. It's highly configurable by users. You can subscribe/unsubscribe simply with mail messages. There is optional subscription/unsubscription confirmation, subscription moderation, message moderation, digest message mode, parent/children list management, mail scheduling to postpone/repeat a message, mail filter (procmail-like syntax), message queue for unsent emails, message size check, command to retrieve messages, bounce detection, message header management, black/white/allow/deny list and others functions. There is also a program to test list settings without sending any message and another program to view/search stored messages. You can configure it with programs like phpMyAdmin.