AUC (Authenticated User Community) is an intranet system designed for use in an educational organization but is also useful in many other settings. It offers the ability for users to have a uniform web-based interface to discussion forums, e-mail (similar to hotmail, etc.), file management, and a searchable user database. Also, "Interactive Classrooms" provide a means for students and teachers to have a web-based extension to their in-class interaction. The system runs from a C-based monolithic CGI script. MySQL is used for database storage. Also, the web-based mail client supports MIME parts/attachments, IMAP, mbox, and multiple mail folders.
dict_pgsql is a dictionary for the mailer postfix. It is able to get all virtual users out of a postgres database; this is very helpful if you have a large number of users who make updates on their aliases quite often. You don't have to extract all the values into system files; the entries will be fetched directly from the database.
E*Reminders is a series of PHP scripts that interact with a MySQL database to setup email reminders for any events or occasions you'd like. It includes recurring reminders, advance notices, and password authentication for email addresses. It can be used for an entire company, as a service for Internet users on your site, or privately.
ldap-abook is an LDAP-based addressbook application, intended for users wishing to maintain a centralized server based addressbook. It provides a schema for an LDAP directory, a Perl library module, and a CGI script. The Web interface is used to view, add, modify, and delete entries. Any LDAP-aware email client (eg. Netscape Messenger, Microsoft Outlook, Lotus Notes, etc.) can be configured to look up email addresses on the LDAP server. The package also includes a Perl script which can be used to dump the directory onto a PalmOS device.
Postlister is yet another PHP/SQL mailing list program. It features an unlimited number of lists, subscription confirmation, no browser time-out, different signature for each list, language files, and a password-protected browser-based administration area that allows you to create/delete/edit lists, find/add/delete subscribers, and preview/send mail to the list(s).