Registered user sends page link to e-mail, plus flames.

"Missive is an application for keeping in touch with the people who matter most to you, via email. Whether it's a dozen friends or ten thousand customers, Missive will help you stay connected."

"popa3d is a tiny POP3 daemon designed with security as the primary goal."

"Introducing Correo, a new open-source mail client for Mac OS X. Correo blends technology from two popular Mozilla projects, Camino and Thunderbird, to create a polished native Macintosh application."

OS X nightly (well, weekly) builds of Thunderbird with Address Book integration patched in.

Shareware Mail.app plugin, keyboard UI for quickly filing messages. Might be worth $8 for the right kind of person.

How to build/acquire a Thunderbird which can read from your OS X address book. Working well for me, so far!

UI, search tweaks and an intro / setup guide to Mail Act-On.