EPRs, MAPs and MEPs

As there has been some confusion:

WSA defines two core concepts: Endpoint References (EPRs) and Message
Addressing Properties (MAPs).

    * EPRs provide a data representation for a destination for
      messages.  Basically an IRI [address], [reference parameters]
      which are to be attached to the message sent (as SOAP headers in
      the SOAP binding), and [metadata], which is anything else of interest.
    * MAPs are analogous to the usual email headers such as from: to:
      reply-to: message-id: and in-reply-to: and, as the name suggests,
      are properties of the message.  There is also an [action] MAP
      defined analogous to the SOAPAction HTTP header.

As should be clear, a MAP is not the same as a MEP.  The names are
confusing, but (one hopes) which one is meant should also generally be
clear from context.