Anti-Spam SMTP Proxy Server implements multiple spam filters
SMTP email proxy and relay server
Powerful Open Source Email Marketing app with analytics & segmentation
Fast Bayesian spam filter along lines suggested by Paul Graham
mailbox synchronizer
Client daemon to move mail from POP and IMAP to your local computer
Chat Messenger. E-Mail-Client. Websearch. Filetransfer.
Strong Email & Apache Log Analysis with Active Security Features
Booking/reservation of meeting rooms/equipment with e-mail invitations
Gross greylisting server
Remote anti spam utility
software for email automation (newsletters, transaction mails, etc.)
Unified Communications Server
Simple Libravatar compatible avatar image server
Script set to archive emails at groupwise server side