you can auto assign people to a particular role at user creation, and then give that role comments and the other roles not:
http://drupal.org/project/autoassignrole
Johns, Ethan wrote:
I am running a college newspaper site and have several user roles established including ones for Section Editors and Copy Editors.
I would like to restrict the Section Editors and Copy Editors roles from posting comments on that site. I can find no way to do this, since these users are also a member of Authenticated Users which includes a broader base of users who should have the ability of posting comments…other than creating a new role for regular users (which I am unsure how to make this the default role for new users), is there a way to restrict the Section Editors and Copy Editors from posting comments?
Thanks!