this might be covered at the nasw ne conference in sept.
keynote speaker will be speaking about ethics in the digital age:
that said, I think that if I were doing a newsletter through one of these services, it would have to be ‘opt-in’ only. Let people sign up through your website, current clients could be told about the newsletter, and could sign up while in for a session.
Past clients, I think, could be sent an email once, with a sample newsletter attached, or linked in the email….. with an invitation to sign up. then the mail chimp or constant contact link included. some will open but not respond, others might. and….. there should always be a simple way to unsubscribe, so that it is transparent that they can reverse the decision. of course, be clear that you will not sell or rent your list to another vendor or enterprise…..