The mailing list is a normal majordomo mailing list.
You can subscribe to the mailing list by e-mail to helpers-request@oekonux-conference.org. The text of the mail must contain exactly the word subscribe. Subject doesn't matter.
You may also unsubscribe by sending an e-mail to helpers-request@oekonux-conference.org. The text of the mail must contain exactly the word unsubscribe.