usefor-article-13 May 2004

8.6.  Duties of a Followup Agent

   A Followup Agent is a special case of a posting agent, and as such is
   bound by all the posting agent's requirements. Followup agents MUST
   create valid followups and are subject to special requirements
   involving certain inheritable (4.2.5.2) and other headers.  Wherever
   in the following it is stated that, "by default", a header is to be
   taken from some header in the precursor, it means that its initial
   content (plus its extension-parameters, if any) are to be copied from
   those of that precursor header.  However, posters MAY then override
   that default before posting if they so wish.

        NOTE: There is no provision in this standard for a followup to
        have more than one precursor (though it might be permitted in
        some future extension).

   1. The Newsgroups-header (5.5) SHOULD by default be taken from the
      precursor's Followup-To-header if present, and otherwise from the
      precursor's Newsgroups-header. However, if the content of that
      Followup-To-header consists of "poster" (and the user does not
      override it), then the followup MUST NOT be posted but, rather, is
      to be emailed to the precursor's poster.

   2. The Subject-header SHOULD by default be taken from that of the
      precursor's Subject-header. The case sensitive string "Re: "
      (known as a "back reference") MAY be prepended to its Subject-
      Content unless it already begins with that string.

        NOTE: The practice of prepending such a "Re: " (which is an
        abbreviation for the Latin "In re", meaning "in the matter of",
        and not an abbreviation of "Reference" as is sometimes
        erroneously supposed) is widespread, but reading agents cannot
        rely on all followup Subject-headers using it, nor can it be
        assumed that reading agents will understand any back-reference
        other than a single "Re: ".
[Shmuel wants something like "... nor that the "Re:" was even intended
as a back-reference."]

        Some reading agents, notably those which choose to use the
        Subject-header to enable a simple form of thread sorting, need
        to be able to recognize the presence of a back-reference.

[Various other snippets of text have been suggested for the NOTE,
including the following:

        NOTE:  Some reading agents expect a single "Re: " at the
        beginning of the Subject-content of a followup, and consider
        this when sorting articles for display.  This is unreliable, and
        an intrusion on the unstructured nature of the header, but
        widespread.

        NOTE: Some reading agents expect this string at the beginning of
        the Subject-content of a followup, and consider this when
        sorting articles for display. Further, most expect just one
        instance of "Re: ", and do not treat any other string in this
        manner.

        NOTE: Further discussion of this (user interface) issue can be
        found in [USEAGE] section x.x.

        Although "Re: " is case-sensitive, there has historically been
        some disagreement about that, so it is best to check for its
        presence with a case-insensitive test.
End of snippets.]

   3. The Distribution-header (6.6) SHOULD by default be taken from the
      precursor's Distribution-header, if any.

   4. If the precursor did not have a References-header (6.10), the
      followup's References-content MUST be formed by the message
      identifier of the precursor. A followup to an article which had a
      References-header MUST have a References-header containing the
      precursor's References-content (subject to trimming as described
      below) plus the precursor's message identifier appended to the end
      of the list (separated from it by CFWS).

      Followup agents MAY trim References-headers which have grown to
      excessive length, but the first and last message identifiers from
      the precursor MUST NOT be removed.

   5. If the precursor contains a Mail-Copies-To-header (6.8), the
      actions to be taken, in accordance with the Mail-Copies-To-
      content, (and subject to manual override by the poster) are as
      follows:

      "nobody" (or when the header is absent)
  The followup agent SHOULD NOT email a copy of a posted
  followup to the poster of the precursor.

      "poster"
  The followup agent SHOULD (if it has the necessary
  capability) email a copy of a posted followup, which MUST
  then be sent to the address(es) in the Reply-To-header, and
  in the absence of that to the address(es) in the From-
  header.

      a copy-addr
  The followup agent SHOULD likewise email a copy of a posted
  followup, which MUST then be sent to the copy-addr.

      When emailing a copy, the followup agent SHOULD also include a
      "Posted-And-Mailed: yes" header (6.9).

      Followup agents SHOULD NOT attempt to send email to any address
      ending in ".invalid".

--- ../usefor-article-12/Duties_of_a_Followup_Agent.out          November 2003
+++ ../usefor-article-13/Duties_of_a_Followup_Agent.out          May 2004
@@ -1,42 +1,70 @@
 8.6.  Duties of a Followup Agent
 
-   A Followup Agent is a special case of a posting agent and as such is
+   A Followup Agent is a special case of a posting agent, and as such is
    bound by all the posting agent's requirements. Followup agents MUST
-   create valid followups and are subject to the following special
-   requirements involving certain inheritable (4.2.5.2) and other
-   headers.
-
-   1. The Newsgroups-header (5.5) SHOULD be initialized from the
-      precursor's Followup-To-header, if present and otherwise from the
-      precursor's Newsgroups-header, when preparing a followup; however
-      posters MAY then change this before posting if they wish.
-
-   2. The Subject-content (5.4) of the precursor MAY (and usually will)
-      be prepended with the back-reference "Re: " (which is case
-      sensitive), unless that precursor is itself a followup with "Re: "
-      already present in its Subject-content; however posters MAY then
-      change this before posting if they wish.  The prepended "Re: "
-      SHOULD NOT be contained within any encoded-word in the new
-      Subject-content.
-
-      Followup agents SHOULD NOT use any other string except "Re: " as a
-      back-reference, and specifically NOT a translation of "Re: " into
-      a local language, and they SHOULD NOT prepend a "Re: " if one is
-      already present.
-[The provision of back-references and their allowed forms are still
-under discussion in the Usefor Working Group.]
-
-        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. Reading agents often take note
-        of a single "Re: " at the beginning of a Subject-content (for
-        example, in order to display a list of articles sorted by
-        Subject). These restrictions ensure that reading agents have no
-        need to recognize more than a single occurrence of "Re: ".
-
-   3. The Distribution-header (6.6) SHOULD be initialized from the
-      precursor's Distribution-header, if any; however posters MAY then
-      change this before posting if they wish.
+   create valid followups and are subject to special requirements
+   involving certain inheritable (4.2.5.2) and other headers.  Wherever
+   in the following it is stated that, "by default", a header is to be
+   taken from some header in the precursor, it means that its initial
+   content (plus its extension-parameters, if any) are to be copied from
+   those of that precursor header.  However, posters MAY then override
+   that default before posting if they so wish.
+
+        NOTE: There is no provision in this standard for a followup to
+        have more than one precursor (though it might be permitted in
+        some future extension).
+
+   1. The Newsgroups-header (5.5) SHOULD by default be taken from the
+      precursor's Followup-To-header if present, and otherwise from the
+      precursor's Newsgroups-header. However, if the content of that
+      Followup-To-header consists of "poster" (and the user does not
+      override it), then the followup MUST NOT be posted but, rather, is
+      to be emailed to the precursor's poster.
+
+   2. The Subject-header SHOULD by default be taken from that of the
+      precursor's Subject-header. The case sensitive string "Re: "
+      (known as a "back reference") MAY be prepended to its Subject-
+      Content unless it already begins with that string.
+
+        NOTE: The practice of prepending such a "Re: " (which is an
+        abbreviation for the Latin "In re", meaning "in the matter of",
+        and not an abbreviation of "Reference" as is sometimes
+        erroneously supposed) is widespread, but reading agents cannot
+        rely on all followup Subject-headers using it, nor can it be
+        assumed that reading agents will understand any back-reference
+        other than a single "Re: ".
+[Shmuel wants something like "... nor that the "Re:" was even intended
+as a back-reference."]
+
+        Some reading agents, notably those which choose to use the
+        Subject-header to enable a simple form of thread sorting, need
+        to be able to recognize the presence of a back-reference.
+
+[Various other snippets of text have been suggested for the NOTE,
+including the following:
+
+        NOTE:  Some reading agents expect a single "Re: " at the
+        beginning of the Subject-content of a followup, and consider
+        this when sorting articles for display.  This is unreliable, and
+        an intrusion on the unstructured nature of the header, but
+        widespread.
+
+        NOTE: Some reading agents expect this string at the beginning of
+        the Subject-content of a followup, and consider this when
+        sorting articles for display. Further, most expect just one
+        instance of "Re: ", and do not treat any other string in this
+        manner.
+
+        NOTE: Further discussion of this (user interface) issue can be
+        found in [USEAGE] section x.x.
+
+        Although "Re: " is case-sensitive, there has historically been
+        some disagreement about that, so it is best to check for its
+        presence with a case-insensitive test.
+End of snippets.]
+
+   3. The Distribution-header (6.6) SHOULD by default be taken from the
+      precursor's Distribution-header, if any.
 
    4. If the precursor did not have a References-header (6.10), the
       followup's References-content MUST be formed by the message
@@ -56,17 +84,18 @@
       follows:
 
       "nobody" (or when the header is absent)
-  The followup agent SHOULD NOT email a copy of the followup
-  to the poster of the precursor.
+  The followup agent SHOULD NOT email a copy of a posted
+  followup to the poster of the precursor.
 
       "poster"
   The followup agent SHOULD (if it has the necessary
-  capability) email a copy of the followup, which MUST then be
-  sent to the address(es) in the Reply-To-header, and in the
-  absence of that to the address(es) in the From-header.
+  capability) email a copy of a posted followup, which MUST
+  then be sent to the address(es) in the Reply-To-header, and
+  in the absence of that to the address(es) in the From-
+  header.
 
       a copy-addr
-  The followup agent SHOULD likewise email a copy of the
+  The followup agent SHOULD likewise email a copy of a posted
   followup, which MUST then be sent to the copy-addr.
 
       When emailing a copy, the followup agent SHOULD also include a