"Freedom" of Speech

The Huffington Post made the New York Times when it announced it was going to stop allowing anonymous comments. We're all familiar with the phrase "on the internet, no one knows you're a dog". We all have avatars, screen names, and multiple email addresses. But to comment anonymously, is that freedom of speech?

Comments on newspapers here in the UK have been moderated and link to profiles for some time. The Scotsman does not require a full profile, but you need to supply an email address to sign up. Other papers require them as well.

So is it really such a shock that US newspapers are restricting anonymous comments? Is it such a threat to freedom of speech? I don't know.