I really hope this is not true. It's the first time I've seen it reported anywhere. But if indeed you can't "annoy" someone online anonymously, then I would like to see charges brought against a blogger named Publius. [Note: If there is actually any such blogger, I have nothing against him/her, I just want the irony.]
UPDATE: As commenter Tom T. points out, Prof. Volokh has his thoughts here and here, while Prof. Kerr has his initial thoughts here. Neither of them, however, posts under a pseudonym, but I have mentioned how Volokh annoys me with his sales pitches for Academic Legal Writing.