A supplements maker has taken to the Amazon.com marketplace to threaten legal action against those leaving negative reviews.

Ubervita, a Washington state company that sells testosterone boosters, multivitamins, and weight loss supplements, has been responding in the comments section under its products to blast those leaving negative reviews. The firm has suggested that some of the negative reviews are libel and defamation and could land the reviewer in a "lot of legal trouble."

The company's comments, which appear to have been removed but are captured here (PDF), began shortly after the company sued for, and eventually won, a subpoena to unmask "negative" Amazon.com reviewers in July.

"It's bullying. They got this overboard order and they took advantage of it," Paul Alan Levy, an attorney for Public Citizen, said in a telephone interview.

Ubervita's attorney, Mike Atkins, declined comment. Amazon did not immediately respond for comment.

In one comment, the company tells an Amazon.com reviewer, "You should probably stop before you get into a lot of legal trouble." Another comment urges a Google search for a recent Ars story about the judge's order, saying, "Google this headline: 'Judge orders unmasking of Amazon.com 'negative reviewers.'" Another line reads, "We will issue subpoena's to learn the identities of those behind this campaign of dirty tricks against Ubervita in a wrongful effort to put Ubervita at a competitive disadvantage in the marketplace."

For his part, Levy is representing a reviewer whose negative comment was met with one of the responses from Ubervita on Amazon.com. In a blog post, Levy blasted the supplement firm's actions, saying, "Even worse, Ubervita had started invoking Judge Pechman’s decision to post responses to critical comments, including comments made AFTER the lawsuit was filed which therefore could not have been alleged in the lawsuit to be false and defamatory, warning that Ubervita was suing its critics and inviting commenters to conduct a Google search to learn about the case—presumably, directing them to the Ars Technica article that warned of the supposed 'unmasking' order."

Ubervita won the power of subpoena last week based on its lawsuit, claiming that unknown Amazon.com commenters placed fraudulent orders "to disrupt Ubervita's inventory," posted a Craigslist ad "to offer cash for favorable reviews of Ubervita products," and posed "as dissatisfied Ubervita customers in posting phony negative reviews of Ubervita products, in part based on the false claim that Ubervita pays for positive reviews."

US District Judge Marsha Pechman gave Ubervita everything it wanted, granting the firm the right to subpoena Amazon and Craigslist to divulge, in Levy's words, the identity of "every Ubervita critic."

Judge Pechman ruled last week that "Ubervita may serve subpoenas on Amazon, Inc. (or other appropriate Amazon entity) and Craigslist, Inc. (or other Craigslist entity) intended to learn the John Doe defendants’ identities, including their names, addresses, telephone numbers, e-mail addresses, IP addresses, Web hosts, credit card information, bank account information, and any other identifying information."

Instead of intervening in court, Levy said he brokered a deal with Ubervita to limit the scope of the subpoena.

"In response to my request to meet and confer about this discovery motion, Ubervita’s lawyer, Mike Atkins, explained that his client’s main objective was to identify the individuals, believed to be connected with a competitor, who had placed phony bulk orders of his client’s product on Amazon, causing the product to be shown as out of stock, and who had placed a phony ad on Craigslist, purporting to be from his client, offering to pay for positive Amazon reviews, and then posted a commentary on Amazon pointing to that ad immediately after it appeared," Levy said on the Public Citizen blog. "To avoid our motion for reconsideration, Atkins agreed to limit his subpoena to Amazon to those issues, thus protecting the larger group of Ubervita critics."

Levy said he was satisfied with Atkins' response.