A simple and fast cross-platform solution to send mass emails.
Gross greylisting server
Booking/reservation of meeting rooms/equipment with e-mail invitations
software for email automation (newsletters, transaction mails, etc.)
Multi-protocol server written in Java
Jnestor is another majordomo in java
IMAP to IMAP Copy
CheckeredFlag is a super simple mail server.
An unofficial web console to administer Apache James 3 server
Drosera is open-source orienteering management server.