It appears the Comments functionality on my site is broken, http://rf-photography.ca. Not sure how long it's been that way but someone notified me of it today.
I've done a search and found an old thread, http://wordpress.org/support/topic/comments-not-working-12?replies=9 indicating that there could be a problem with the .htaccess file. I made changes to that based on this article, http://codex.wordpress.org/Using_Permalinks but still Comments are broken.
I've turned off Comments for the time being.