On Thu, 09 Oct 2014, PeteCresswell wrote to All:

 P> Per David H. Lipman:
 DHL>*  Always use the BCC field when emailing a number of recipients or
 DHL>using a Distribution List (aka; D-List)

 P> I always assumed that was Good Practice just on the basis of not
 P> throwing around people's email addresses in the open... but now that
 P> I'm thinking about it, wouldn't the BCC list be just as easy to
 P> extract from an intercepted email as would any other field?

other than on the originating machine, the BCC only exists for the envelope of
the message... it is not stored anywhere else with the message thus the reason
for the 'B' meaning 'Blind'...

so it works like this... when the messages are being packaged to be sent to the
remote SMTP server(s), each BCC entry has its own envelope created with the
published fields and a copy of the message... BCC is not a published field...
the envelope with the message is sent to the remote server handling mail for
that BCC entry... when the server receives the envelope and message, it
processes it and throws away the envelope while placing the message in the
destination's mailbox... transitory servers read the envelope and pass it on to
the next server with the message...

that's a pretty simple explanation but it is also fairly accurate ;) 

)\/(ark