I don't have newsletters for my website. From the perspective of a forum member, I don't usually read forum newsletters unless they are a big site or a site I am really active it. I am not sure how well a newsletter would work...would probably just end up in junk. Maybe, you could have the option when the user registers if they want to receive the newsletter or not.
I wouldn't use them at all. In all honesty, newsletters and email updates just annoy me and get promptly deleted unless I know they are from a site which I will care about. Of course, the majority of ones I get just end up in my junk anyway with all the friendly kings offering me money so I would never read them anyway.
I have one installed and was using it up until when members started writing to me about not sending newsletters and fill their inboxes.
We use them to send important updates and product deals and offers to forum members. In fact this was put in practice upon request from a handful of nonregulars
