Would it be possible to give regular visitors (not subscribers) a login option to be able to view and track correspondence they've sent to businesses listed in the directory etc? I guess I'm really asking whether there could be two types of account with different admin areas?
By default there is really only one user type, so it would require customization on your part if you were looking to allow other types with limited access as you describe. There is no specific feature for this already built into the theme. Thanks.