Is a powerful web based mail list manager. It will meet most of your needs for handling any size mailing list.

VisNetic Mail Server is a multi-featured mail server that will scale to meet the email and instant messaging needs of any sized organization, including ISP and ASP environments.

an email scanning agent that searches email waiting at their ISP, or from any POP3 or IMAP server, applying user-specified conditions, like looking for specific text content, or "from" a specific person, or specific words in the "subject" etc.