usefor-article-11 June 2003

5.4.  Subject

   The Subject-header contains a short string identifying the topic of
   the message. This is an inheritable header (4.2.5.2), normally to be
   copied into the Subject-header of any followup with the possible
   addition of a back-reference as described in B.6.

      header              =/ Subject-header
      Subject-header      = "Subject" ":" SP Subject-content
      Subject-content     = unstructured

        NOTE: The syntax of unstructured differs from that prescribed in
        [RFC 2822], so ensuring that the Subject-content is not
        permitted to be completely empty, or to consist of WSP only (see
        remarks in 4.2.6 concerning undesirable headers).

--- ../usefor-article-10/Subject.out          April 2003
+++ ../usefor-article-11/Subject.out          June 2003
@@ -1,49 +1,16 @@
 5.4.  Subject
 
    The Subject-header contains a short string identifying the topic of
-   the message. This is an inheritable header (4.2.5.2) to be copied
-   into the Subject-header of any followup, in which case the new
-   Subject-content SHOULD then default to the string "Re: " (a "back
-   reference") followed by the contents of the pure-subject of the
-   precursor. Any leading "Re: " in that pure-subject MUST be stripped.
+   the message. This is an inheritable header (4.2.5.2), normally to be
+   copied into the Subject-header of any followup with the possible
+   addition of a back-reference as described in B.6.
 
       header              =/ Subject-header
       Subject-header      = "Subject" ":" SP Subject-content
-      Subject-content     = [ [FWS] back-reference ] pure-subject
-      pure-subject        = unstructured
-      back-reference      = %x52.65.3A.20
-                          ; which is a case-sensitive "Re: "
-
-   The pure-subject MUST NOT begin with "Re: ".
+      Subject-content     = unstructured
 
         NOTE: The syntax of unstructured differs from that prescribed in
         [RFC 2822], so ensuring that the Subject-content is not
         permitted to be completely empty, or to consist of WSP only (see
         remarks in 4.2.6 concerning undesirable headers).
-
-   Followup agents MAY remove strings that are known to be used
-   erroneously as back-reference (such as "Re(2): ", "Re:", "RE: ", or
-   "Sv: ") from the Subject-content when composing the subject of a
-   followup, and add a correct back-reference in front of the result.
-
-        NOTE: that would be "SHOULD remove instances" except that we
-        cannot find a sufficiently robust and simple algorithm to do the
-        necessary natural language processing.
-
-   Followup agents MUST NOT use any other string except "Re: " as a back
-   reference. Specifically, a translation of "Re: " into a local
-   language or usage MUST NOT be used.
-
-        NOTE: "Re" is an abbreviation for the Latin "In re", meaning "in
-        the matter of", and not an abbreviation of "Reference" as is
-        sometimes erroneously supposed.
-
-
-   Agents SHOULD NOT depend on nor enforce the use of back references by
-   followup agents.
-
-   For compatibility with legacy news software, the Subject-content of a
-   control message (i.e. an article that also contains a Control-header)
-   MAY start with the string "cmsg ", and non-control messages MUST NOT
-   start with the string "cmsg ". See also section 6.13.