In order to leave a comment for Peter you must either login via Facebook, Google+, Twitter or DISQUS.
You can alternatively login as a guest simply using your name and email address. ( See Instuctions)
Logging in as a guest:
First enter your comment, once you click the comment field a drop down box will show for you to fill in your name and email address.
Complete these fields and then use the scroll bar on the right hand side of the discussion box to see the login as a guest option.
Finally simply check 'the post as guest' option.