You can subscribe to the list through email, no need to do it through web site. As far as I have read at other lists information based on "mailman":
Send an e-mail message to
No subject nor body seem needed to that message, just that address.
You should receive a confirmation message back telling you if your request to subscribe to the list has succeeded or to confirm the subscription request.
See this page with much more detailed informagtion about how to use the email interface of mailman lists (subscribe, unsubscribe, set options, ...), such as the ones used by Tikiwiki community!
Finally, for completeness, you can subscribe through a web interface from here:
If it works, you can add that somewhere at the documentation!