... but as it happens there is a pretty clear and simple model for
the semantics that attach to bcc. We didn't come up with it - in fact
all the way back to typewriters and hand manipulation of copies and
between them - but it's a model nevertheless. And many if not most of the
technical details of how you implement this stuff follow directly from
X.400 documented this pretty clearly. If we're going to discuss a model
for Internet Mail, it'd be worth at least using that as a starting point.