SpamAssassin - Use this program to "Unspam" your mailbox(es).
/Tab - The simple way to split a bill among friends.
MailScanner - MailScanner is a open source email security system design for Linux-based email gateways.
Splitwise - Splitwise is a free tool for friends and roommates to track bills and other shared expenses, so that everyone gets paid back. On the web, iPhone, and Android!
Rspamd - Rspamd is an advanced spam filtering system that allows evaluation of messages by a number of rules...
Splittable - Shared living made simple