There are two mailing lists covering the county of Derbyshire, England and each has its own archive of messages.
The Rootsweb mailing list is Derbysgen. This list has threaded archives and searchable archives as follows:
The British-Genealogy.com list is Eng-Derbyshire. This list has archives that can be viewed by author, date, subject or thread and you have to be a subscriber to view them.
If you are already a subscriber go to Eng-Derbyshire, click on the archive link and login using the email address and password you used to subscribe.
If you are not a subscriber go to the above link, subscribe, reply to the confirmation email and then you can access the archives using the instructions above.