As a followup to problems some of you have been having with leaving comments, I refer you to the link below:
The upshot: if you have a WordPress.com account, and you try to comment using your email address but without signing in to WordPress, the system won’t allow it. The solution is to either sign in to your WP account, or use an email that is not attached to a WP account.
Because this system is causing some regular commenters a lot of problems, I am going to experiment with allowing anonymous comments for now. I hope, however, that you will continue to leave your id information or to log in to comment, as I like knowing who you are! I may revert to login-only comments at a later date.