We’ve activated an anti-comment-spam option that’s new in WordPress 1.5: comments from authors with previously approved comments are whitelisted, and all other comments are queued for approval (or deletion) by us. The whitelisting is keyed on email address, so if you don’t provide an email address, your comment will be queued for moderation. To be clear: you aren’t required to provide an email address when you post a comment, but if you don’t, or if you’re commenting for the first time, your comment will not appear immediately. We get a few dozen comment spams a day, so we have a lot to sift through—if your comment doesn’t appear for several hours, don’t worry, and please don’t try to post it again.
Also, our WordPress seems to be having trouble remembering comment-author names—it should remember your name if you have cookies enabled—so check to see if your name has been filled in before you publish a comment. Hopefully we’ll have this minor problem fixed soon.
