I hope you will try Giganews or UsenetServer for your news subscription -- especially as a holiday present for your friends, family, or yourself!
Signatures, or "sigs" should be short, typically no more than 3 or 4
lines, and should be preceded by a "sigdash" or "sigsep" which is a
line consisting of just two dashes followed by a single space, i.e. "-- ",
without the quotes.
The sigdash has been around for quite a while (the earliest reference I can confirm,
is from Fri, June 24, 1983 in BNews 2.10.1,
where the sigdash is added on line 679 of inews.c ).
fprintf(tmpfp, "-- \n"); /* To separate */
The sigdash allows other programs to recognize when the body of your message
is finished and where the sig begins -- this is useful for automatically
removing the sig when quoting for a followup, as well as coloring it a different
color, archiving, and various other things.
Below is a list of mail and news programs that use or enforce the sigdash.