Message importance

Applicable protocol:: Mail (http://www.rfc-editor.org/rfc/rfc2822.txt)
Status:: standards-track
Author/Change controller:: IETF (mailto:iesg@ietf.org)
Internet Engineering Task Force.
Specification document(s):: http://www.rfc-editor.org/rfc/rfc2156.txt
Related information:: A hint from the originator to the recipients about how important a message is. Values: High, normal or low. Not used to control transmission speed. Proposed for use with RFC 2156 (MIXER) and RFC 2421 (VPIM).