usefor-article-04 April 2001

6.19.1.5.  The posting-date-parameter

   This parameter identifies the time at which the article was injected
   (as distinct from the Date header, which indicates when it was
   written). It is in the form of the number of seconds elapsed since
   January 1st 1970, optionally followed by a date-time which MUST
   indicate the same time.