I think an opportunity was missed here. Instead of pitching publishers, he should have taken some time out to pitch a politician or two. What? Yes, that's right. Nobody hates anonymous commenting more than politicians, and every now and again, one tries to force registrations for comments. If you laid the groundwork (assuming the service is still around), at the right moment (say, when an anonymous commenter really does something to inflame opinions) you could pitch a politician to try and get the idea legislated into existence for certain types of publishing.

Granted it's not an easy strategy or a usual one, but corporations have been legislating themselves into business for years, so it would be worth a try.