Jim Winstead <jimw@trainedmonkey.com>: the core "command dispatch"
system in qpsmtpd is taken from his colobus nntp server.  The
check_badmailfrom and check_mailrcptto plugins.

John Peacock <jpeacock@cpan.org>: More changes, fixes and vast
improvements for me to ever catch up on here.

Matt Sergeant <matt@sergeant.org>: Clamav plugin.  Patch for the dnsbl
plugin to give us all the dns results.  Resident SpamAssassin guru.
PPerl. smtp-forward plugin. Documentation (yay!).  Lots of fixes and
tweaks.  Apache module.  Event based high performance experiment.

Devin Carraway <qpsmtpd@devin.com>: Patch to not accept half mails if
the connection gets dropped at the wrong moment.  Support and enable
taint checking. MAIL FROM host dns check configurable.  HELO hook.
initial earlytalker plugin.

Andrew Pam <xanni@glasswings.com.au>: fixing the maximum message size
(databytes) stuff.

Marius Kjeldahl <marius@kjeldahl.net>, Zukka Zitting
<jukka.zitting@iki.fi>: Patches for supporting $ENV{RELAYCLIENT}

Robert Spier <robert@perl.org>: Klez filter.

Rasjid Wilcox <rasjidw@openminddev.net>: Lots of patches as per the
Changes file.

Kee Hinckley <nazgul@somewhere.com>: Sent me the correct strftime
format for the dates in the "Received" headers.

Gergely Risko <risko@risko.hu>: Fixed timeout bug when the client sent
DATA and then stopped before sending the next line.

... and many many others per the Changes file and subversion logs and
    mailing list archives.  Thanks everyone!