OK, have done a bit more research. If anyone can comment on my
following thoughts, please do so.

So, I would set up a custom field for the contacts, for example a
YES/NO type field called "Replied to January 2007 mailing".

For (Q2) I can create a custom view of my contacts that would only
show those contacts where the "Replied to January 2007 mailing" is set
to NO (still at default.)

(I do not know how to turn this custom view into a mailing list though.
The Outlook help pages were no help.)

Regarding (Q1) I still do not know how the receipt of an email would
cause the corresponding email address in a contact to change the
"Replied to January 2007 mailing" field to YES. Am I right in thinking
that this requires some VB coding?

Once again, thanks in advance for any replies.

Miner2049er.