Due to mass amounts of spam, submitting comments is now restricted to registered users. However, user registration is unlocked so that admin intervention is no longer needed to register an account. It does use the captcha plugin to dissuade spam, though. This will ask a simple mathematical question in the registration form.
Newly registered users are in the guest
group by default, which confers no rights to edit or create any pages anywhere in the wiki. However, submitting comments is allowed.
As before, every comment is screened by the moderation before it shows up.