usefor-article-03 February 2000

6.9.  Expires

   The  Expires  header specifies a date and time when the article is
   deemed to be no longer relevant and  could usefully  be removed
   ("expired"). The content syntax makes use of syntax defined in
   [MESSFOR].

      Expires-content     = date-time

   An Expires header should only be used in an article if the requested
   expiry time is earlier or later than the time typically to be
   expected for such articles. Local policy for each serving agent will
   dictate whether and when this header is obeyed and authors SHOULD NOT
   depend on it being completely followed.

--- ../s-o-1036/Expires.out          June 1994
+++ ../usefor-article-03/Expires.out          February 2000
@@ -1,37 +1,15 @@
-6.2. Expires
+6.9.  Expires
 
-The  Expires  header  content specifies a date and time when
-the article is deemed to be no longer useful and  should  be
-removed ("expired"):
+   The  Expires  header specifies a date and time when the article is
+   deemed to be no longer relevant and  could usefully  be removed
+   ("expired"). The content syntax makes use of syntax defined in
+   [MESSFOR].
 
-     Expires-content = Date-content
+      Expires-content     = date-time
 
-The  content syntax is the same as that of the Date content.
-In the absence of Expires, the default  is  decided  by  the
-administrators  of  each  host  the article reaches, who MAY
-also restrict the extent to which the Expires header is hon-
-ored.
-
-The Expires header has two main applications: removing arti-
-cles whose utility ends on  a  specific  date  (e.g.,  event
-announcements which can be removed once the day of the event
-is past) and preserving articles expected to be of prolonged
-usefulness  (e.g.,  information  aimed  at  new readers of a
-newsgroup).  The latter  application  is  sometimes  abused.
-Since individual hosts have local policies for expiration of
-news (depending on  available  disk  space,  for  instance),
-posters  SHOULD  not  provide  Expires  headers for articles
-unless there is a natural expiration  date  associated  with
-the  topic.   Posting  agents  MUST  not  provide  a default
-Expires header.  Leave it out and allow local policies to be
-used unless there is a good reason not to.  Expiry dates are
-properly the decision  of  individual  host  administrators;
-posters  and  moderators  SHOULD  set only expiry dates that
-most administrators would agree with.
-
-     NOTE: A poster preparing an Expires header for  an
-     article  whose  utility  ends  on  a  specific day
-     should typically  specify  the  NEXT  day  as  the
-     expiry  date.   A  meeting  on July 7th remains of
-     interest on the 7th.
+   An Expires header should only be used in an article if the requested
+   expiry time is earlier or later than the time typically to be
+   expected for such articles. Local policy for each serving agent will
+   dictate whether and when this header is obeyed and authors SHOULD NOT
+   depend on it being completely followed.