Ouch, I feel old now. Here's the .signature I used at the time, featuring an encoded bit of anti-CDA, presumably illegal under CDA profanity.

    #!/usr/bin/perl -pl-                                     ,,ep) ayf >|)nj,,
    $_=reverse lc$_;s@"@''@g;y/[]{A-U}<>()a-y1-9,!.?`'/][} #         Joey Hess
    {><)(eq)paj6y!fk7wuodbjsfn^mxhl2Eh59L86`i'%,/;s@k@>|@g #  joey@kitenet.net

(Flips text upside down.. we didn't have unicode then..)