Spamato is a spam filter system that combines several anti-spam techniques, from which thousands of users benefit. It is available as an add-on for Thunderbird and Outlook, and as a stand-alone proxy for other email clients. IMAP and POP are supported.
A cross-platform notification daemon written in Ruby. Can be petitioned by an arbitrary application (local or remote) to activate notification plugins. Plugin examples include a popup dialog, a syslog entry, or an email alert.