Hi,
My forums can be read by non-authenticated visitors, but require registration/signon to post. However, most forums that I've seen will show a "Start New Tread" or "Reply" button in ANY case. This way, new visitors will try to start a thread or reply and will see a logon screen with the option to register an account.
Right now, people are confused on what they have to do / where they have to go to post.
I worked around it temporarily by adding an explanation above the forum module reminding people and providing a login/registration prompt.
But, the more untuitive option would be to always show "post" buttons - and just redirect them to login pages, as explained before.
Best Regards,
Andy