usefor-article-03 February 2000

5.6.3.  The tail-entry

   For historical reasons, the tail-entry (i.e. the rightmost entry in
   the Path-content) is regarded as a "user name", and therefore MUST
   NOT be interpreted as a site through which the article has already
   passed. Moreover, the Path-content is not an E-mail address and MUST
   NOT be used to contact the poster. Posting and/or injecting agents
   MAY place any string here. When it is not an actual user name, the
   string "not-for-mail" is often used, but in fact a simple "x" would
   be sufficient.

   Often this field will be the only entry in the region (known as the
   pre-injection region) after the '%', although there may be entries
   corresponding to machines traversed between the posting agent and the
   injecting agent proper. In particular, injecting agents that receive
   articles from many sources SHOULD include the identity of the source
   machine connecting to do the injection, and possibly other
   information enabling them to establish the circumstances of the
   injection (provided it does not conflict with any genuine site
   identifier). The '!'  delimiter may be used freely within the pre-
   injection region, although '/' and '?' are also appropriate if used
   correctly.
[If/when we invent some form of Injector-Info header, we may want to
revisit that paragraph.]