A sig block that has been
included twice in a Usenet article or, less commonly, in an
electronic mail message. An article or message with a doubled sig
can be caused by improperly configured software. More often,
however, it reveals the author's lack of experience in electronic
communication. See B1FF, pseudo.
ig block: /sig blok/ [UNIX; often written `.sig' there] n.
Short for `signature', used specifically to refer to the
electronic signature block that most UNIX mail- and news-posting
software will {automagically} append to outgoing mail and news....