But in order to press that claim, Hadeed Carpet Cleaning would need to know who made those reviews. And so to find out, they subpoenaed Yelp to turn over the identities. Yelp refused, and the case headed to court. Earlier this week, the Court of Appeals of Virginia ruled that Yelp must out its seven anonymous reviewers.

Anonymous speech is a central component of America's First Amendment legacy. The Supreme Court has repeatedly protected the right to speak anonymously, holding in 1960 that, "Anonymous pamphlets, leaflets, brochures and even books have played an important role in the progress of mankind." In 1995 they affirmed that earlier position: "Under our Constitution, anonymous pamphleteering is not a pernicious, fraudulent practice, but an honorable tradition of advocacy and of dissent. Anonymity is a shield from the tyranny of the majority." This right, the Virginia Court of Appeals noted, does not disappear at a website's log-in screen. "The right to free speech is assiduously guarded in all mediums of expression, from the analog to the digital," it held.

That position notwithstanding, the court continued, the right to speak anonymously is not an absolute one: "Defamatory speech is not entitled to constitutional protection."

The court turned to Virginia's state law, which requires, among other things, that the plaintiff need show that the reviews "are or may be tortious or illegal," or that Hadeed Carpet Cleaning has "a legitimate, good faith basis" to believe that they were the victim of actionable conduct. The court held that the lower court's assessment was correct: "If the Doe defendants were not customers of Hadeed, then their Yelp reviews are defamatory." Moreover, the court believed that Hadeed had conducted a sufficient review of its own corporate records to have "a legitimate, good faith basis" for believing the reviewers had invented their claims.

Paul Levy, an attorney at the advocacy group Public Citizen who argued the case for Yelp, says that he believes this is where the court's ruling falters. The standard for a claim of defamation is just too soft, not requiring any showing of falsity or damages.

"They don't say that the substance is false," he told me. "They say, well, we can't be sure this person is a customer. No one with this pseudonym from this city is in our customer database. Well, of course! It's a pseudonym. They haven't shown anything that really would lead any person to believe that this isn't a customer."

Levy and Public citizen believe "If you've been defamed, you ought to be able to [show evidence of your claim of defamation]," Levy says. "And that's both what Hadeed didn't do here—they just refused—they didn't do that here and the court didn't require them to do that." Many other state courts, such as Delaware, Maryland, D.C. (not a state per se, but, alas), Arizona, California, Texas, New Hampshire, and Indiana, have all required supporting evidence in order to unmask the identities of anonymous communicators online.