We know it is confusing and a bit difficult to post comments on our blog (thank whoever designed this template!). The easiest way is just to sign in with your Google account (if you have one), but if you don't have a Google account, do this:
After writing your comment, select Name/URL in the dropdown next to "Comment As". Under "Name", type your name, and under "URL" just type "a.com" or really anything you want, as long as it ends in ".com".
Thanks for keeping up with us, we love to see your comments so keep them coming :).