Boxbe is a socially-powered email screening service that reduces email overload and prioritizes your email. Boxbe helps ensure email from friends is always delivered with priority.
Avelsieve or, verbosely, "Sieve Mail Filters Plugin for Squirrelmail" is a Squirrelmail plugin for creating Sieve scripts on a Sieve-compliant mail server.
Some administrators claim that Reply-To munging makes it easier for users to respond to the entire list, and helps encourage list traffic. These benefits are fallacious. Moreover, Reply-To can have harmful -- even dangerous -- effects. If you think Reply-To munging is a good idea, I hope I can change your mind.