A number of people have provided feedback, corrections, and contributions, as indicated in the Revision History. Thank you!
The following are some of the people and groups that have provided tools and ideas to this document, in no particular order:
Evan Harris <eharris (at) puremagic.com>, who conceived and wrote a white paper on greylisting.
Axel Zinser <fifi (at) hiss.org>, who apparently conceived of teergrubing.
The developers of SPF, RMX++, and other Sender Authorization Schemes.
The creators and maintainers of distributed, collaborative junk mail signature repositories, such as DCC, Razor, and Pyzor.
The creators and maintainers of various DNS blocklists and whitelists, such as SpamCop, SpamHaus, SORBS, CBL, and many others.
The developers of SpamAssassin, who have taken giant leaps forward in developing and integrating various spam filtering techniques into a sophisticated heuristics-based tool.
Tim Jackson <tim (at) timj.co.uk> collated and maintains a list of bogus virus warnings for use with SpamAssassin.
A lot of smart people who developed the excellent Exim MTA, including: Philip Hazel <ph10 (at) cus.cam.ac.uk>, the maintainer; Tom Kistner <tom (at) duncanthrax.net>, who wrote the Exiscan-ACL patch for SMTP-time content checks; Andreas Metzler <ametzler (at) debian.org>, who did a really good job of building the Exim 4 Debian packages.
Many, many others who contributed ideas, software, and other techniques to counter the spam epidemic.
You, for reading this document and your interest in reclaiming e-mail as a useful communication tool