Recommend adding the following paragraph (excuse the XML markup): <t> There are tradeoffs in the decision of what constitutes the "core" of the message, which for some fields is a subjective concept. Including fields such as "Message-ID" for example is useful if one considers a mechanism for being able to distinguish separate instances of the same message to be core content. Similarly, "In-Reply-To" and "References" might be desirable to include if one considers message threading to be a core part of the message. </t>
_______________________________________________ NOTE WELL: This list operates according to http://mipassoc.org/dkim/ietf-list-rules.html