usefor-article-03 February 2000

6.17.3.4.  Multipart types

   The Content-Types "multipart/mixed", "multipart/parallel" and
   "multipart/signed" may be used freely in news articles.  However,
   except where policy or custom so allows, the Content-Type:
   "multipart/alternative" SHOULD NOT be used, on account of the extra
   bandwidth consumed and the difficulty of quoting in followups, but
   reading agents MUST accept it.

   The Content-Type: "multipart/digest" is commended for any article
   composed of multiple messages more conveniently viewed as separate
   entities. The "boundary" should be composed of 28 hyphens (US-ASCII
   45) (which makes each boundary delimiter 30 hyphens, or 32 for the
   final one) so as to accord with current practice for digests [RFC
   1153].
[Actually, this conflicts with some present digest usage (such as the
news.answers rules), but should still be the right way to go. I suggest
this is left in for now (just to stake a claim), while we discuss the
matter with the news.answers moderators and the faq-maintainers.]