The following text was in the spec prior to 2010. It can live here more happily... and form part of the FOAF Wiki historical materials.
Geek Code background
The geekcode property is not bound to any particular version of the code. The last published version of the code was v3.12 in March 1996.
As the Geek Code website notes, the code played a small (but amusing) part in the history of the Internet. The geekcode property exists in acknowledgement of this history. It'll never be 1996 again.
Note that the Geek Code is a densely packed collections of claims about the person it applies to; to express these claims explicitly in RDF/XML would be incredibly verbose. The syntax of the Geek Code allows for '<' and '>' characters, which have special meaning in RDF/XML. Consequently these should be carefully escaped in markup.
An example Geek Code:
GED/J d-- s:++>: a-- C++(++++) ULU++ P+ L++ E---- W+(-) N+++ o+ K+++ w--- O- M+ V-- PS++>$ PE++>$ Y++ PGP++ t- 5+++ X++ R+++>$ tv+ b+ DI+++ D+++ G++++ e++ h r-- y++**
...would be written in FOAF RDF/XML as follows:
<foaf:geekcode> GED/J d-- s:++>: a-- C++(++++) ULU++ P+ L++ E---- W+(-) N+++ o+ K+++ w--- O- M+ V-- PS++>$ PE++>$ Y++ PGP++ t- 5+++ X++ R+++>$ tv+ b+ DI+++ D+++ G++++ e++ h r-- y++** </foaf:geekcode>
See also the geek code entry in everything2, which tells us that the geek code originated in 1993; it was inspired (according to the inventor) by previous "bear", "smurf" and "twink" style-and-sexual-preference codes from lesbian and gay newsgroups. There is also a Geek Code Decoder Page and a form-based generator.