sig block

sig block /sig blok/ n.  [UNIX; often written `.sig'
   there] 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.
   The composition of one's sig can be quite an art form, including an
   ASCII logo or one's choice of witty sayings (see {sig quote},
   {fool file, the}); but many consider large sigs a waste of
   {bandwidth}, and it has been observed that the size of one's sig
   block is usually inversely proportional to one's longevity and
   level of prestige on the net.  See also {doubled sig}.