The mailing lists provide venues for questions and discussion on projects and services JA-SIG provides.
The page for each mailing list has details on how to subscribe, unsubscribe, edit settings and view archives.
To change the configuration of your membership (e.g., your email address, type of membership, password, receiving copies of your own post), click on the Edit Settings link for the list on its page. You can also find additional documentation here.
The list service maintenance window is every Sunday 8am-noon, but is only used when necessary. The service is generally live during that time.