Per action taken at last night ExCom Meeting: Subscribers can now create new Comments and/or respond to existing Comments for Blog Posts that allow Commenting (people entering posts can choose whether to allow commenting or not by blog post).
To become a Subscriber, you need to create a logon (userID and password) for this site by clicking on the button near the top of the right sidebar.
and then enter the quiz answer and your comment:
To reply to an existing comment, enter the quiz answer and your comment:
This only applies to Blog Posts, which can be accessed from the left-hand sidebar.
This does not (yet) apply for site Pages, which are accessible from the menus near the top of the page.