This document is based on an appendix of my thesis "Classifying Galaxies, Gays and Geeks - Signature Codes in Usenet postings". (It's written in finnish, but there's an English summary available.)
Below is a list of 82 codes mentioned in the World Wide Web or in USENET archives. Most of the codes have been removed from their original location. The ones marked with an asterisk (*) are discussed shortly at the end of the document.
The mother of all codes was first used on a mailing list, then in USENET postings and later even in WWW personals -- which was a joke 15 years before.
The far most popular signature code ever. The first one to spread outside soc.motss (or soc.bi). Published by Robert Hayden in 1993 and last updated in 1996. There was an attempt to make it "Y2K compatible" in 1999, but the project silently faded away.
Most of the codes used the same syntax as Donahue and Stoner in their original Natural Bears Calssificaion System (NBCS). So did Hayden's Geek Code. In 1998 Goth Code's author synic "used 6-bit binary encoded ASCII and enabled an extremely large amount of data to be represented in a one and a half line .sig. Very successful but not all that popular with the punters" [synic 2000]. Too bad this 4th version of the code has totally disappeared from the Web -- by the request of the author.
Allthough every signature code has it's humour, these ones have it on a different level.
The Mac Code had a "graphic interface" with smileys instead of pluses or minuses,
the Code Code had fields like "I've written a code", "I've prevented a code from being written" and "number of codes you have completed (optional)"
and the Meta Geek is a "simpler, higher-level code" -- there are only two ways to use it:
gc (I have a Geek Code) or
!gc (I don't have a Geek Code).