To subscribe, send an email to autoshare@mactech.com, with the command:
SUB CHALLENGE YourName
in the SUBJECT line. (Most other listservers take commands in the body, but this particular server's parser has some problems.)
Alternatively, you can subscribe from the comfort of your web browser. Just fill in the email address you wish to subscribe with, and your full name, and click on the subscription button. An email will be generated and sent to the list server.