When you submit a comment on my blog (or any WordPress blog), you have to leave an email. I can see the emails people use.
Some people have left comments as “anon” or “anonymous” or similar, but continued to use the email they post under most of the time. That means I know who left the comment. Obviously, I would never publicly connect an anon’s identity to their main pseudonym; I will hold any information I get this way in confidence. But it’s very legitimate to not trust me, and if you don’t I would suggest using a fake email. (This works fine with WordPress.)