Originally, the blog was set to reject all anonymous comments, and require openID to post comments. I personally believe that is too restrictive, and I know it is frustrating.
Some report having trouble with the new Haloscan comment management system, but many have been able to log in and post comments with no problems. I tested some of the options personally and found it to be quite easy to use. If you find you are unable to log in for some reason, or otherwise unable to leave comments, I apologize, but please contact us and we will try to assist you.