I would like new users to be auto-subscribed, and allow visitors to subscribe to receive email notice of new and updated post, comments, forum comments and newsletters.
WPMU Dev plugins available to do this include Subscribe by Email, e-Newsletter, MailChimp Integration, and Forums. MailChimp obviously creates its own mail list. But do the other's integrate, add to and use the same list?
Or is there a better way to get my desired outcome?