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.
WCN:Talk (originally called "FutureForum") is a Web discussion forum written in Perl and MySQL. It has many options, including message selection and sorting on the top index page. It also has collapsible branches, a menu that toggles between 'no menu', 'simple', and 'advanced' modes, full text search capability, the ability to send email to the admin and original poster, and many other features. It includes password protection, HTML templates, file uploads, message subscription, multiple discussion sections, and a lot more.
aWebDap is an easy-to-use and flexible Web front end to OpenLDAP version 2. It allows one to query, view, create, delete, and modify LDAP entries. It is written with address book suppport in mind. It also supports VCARD, Mapquest/Google maps, LDAP URL address book interface (Outlook), Web-enabled cell phones, and multiple domains. Its capabilities are driven by a configuration file that defines options and user presentation. It can interface with Web servers with CGI support.