Imagine you just purchased a shiny new wireless router from Amazon, only to discover that the product doesn’t work as you anticipated. To vent frustration and perhaps help others avoid the same mistake, you leave a negative product review—but some of your claims ultimately turn out to be incorrect or misleading.

Now the company’s attorneys want to sue you for your "illegal campaign to damage, discredit, defame, and libel” it. Are you going down in flames? Or can you say what you want on the Internet?

As with many areas of law, the answers are nuanced and complicated. Our primer, however, will help you avoid the obvious pitfalls.

Libel law gray area

Last week, we wrote about how lawyers for wireless router manufacturer Mediabridge sent a scathing cease-and-desist letter to a redditor who goes by “trevely," threatening to sue him unless he deleted his negative review of one of the company's products on Amazon. The reviewer instead posted the letter to reddit, setting off a firestorm of negative publicity against the company.

Mediabridge has since responded by posting a letter to its Facebook page noting that it did not sue trevely (it just threatened him) and that Amazon had rescinded the company’s selling license because of its tactics. Mediabridge has since deleted its Facebook and Twitter accounts, and most of the above-referenced information has been taken down.

A number of readers responded to our piece by noting that this is a classic case of the Streisand effect and by offering their two cents on the thorny nature of libel law. For instance, commenter mikexcite noted that “libel law is counter-intuitive and full of scary gray areas.”

We agree. And given how much commerce takes place online these days and the importance of online product reviews to help guide shoppers to the right products, we think this topic is ripe for further consideration.

It's not an academic debate, either. There's an increasing frequency of legal quarrels over online product reviews, so would-be reviewers should be aware of possible legal implications of their actions.

For example, such recent litigation has included a suit filed by a dentist against one of his patients after the patient had written a negative review. Then there's the suit involving nasty reviews of a local building contractor left by a Virginia homeowner on Yelp and Angie's List.

Truth is your best defense

The law surrounding defamation, defined as “the action of damaging the good reputation of someone,” aims to strike a delicate balance between freedom of expression and the requirement that citizens be held responsible for abusing that right (i.e., why you can’t yell “fire” in a crowded theater).

“You can’t guarantee that you won’t get a nasty letter from an aggressive law firm,” Lee Berlik, an attorney who specializes in defamation law, told Ars after reading through the cease-and-desist letter sent to trevely. “But you can certainly take steps to minimize the likelihood of that happening.”

While describing defamation law as somewhat convoluted, Berlik offered up a simple rule of thumb for would-be reviewers. “The big point is that you can’t make stuff up. It’s fairly easy to not get sued as long as you tell the truth," he said. “If you are upset with a company because you don’t like their product and decide to hurt them by making stuff up on a review site, you can get in trouble. But if you have a negative opinion about something and you are acting in good faith in your review, you are protected by the First Amendment.”

Berlik said that in order to satisfy the requirements for a valid defamation action, the suing party has to show that the defendant’s statement is false, that it is defamatory in nature, and that the defendant acted with a certain level of intent. If, for example, a large and well-known company files suit for defamation, Berlik said that “the company must establish ‘actual malice’—that the person knew what he was saying was false or acted with reckless disregard for the truth."

Analyzing trevely’s situation—and specifically Mediabridge's claim that trevely wrote, “this is a rebranded $20 router from China”—Berlik explained that if trevely knew his review was a false statement of fact and that he wrote it with the intention of harming the company, then it is likely defamatory.

However, Berlik pointed out that in the text of the review transcribed in the cease-and-desist letter, trevely published a link allegedly showing that the Mediabridge router is the same as the $20 router from a company called Tenda, writing, “The FCC filings for Medialink confirms that it is the same product.” Berlik noted that if Medialink is considered a “public figure,” trevely's citation to the FCC filing likely supports his review, assuming he was acting in good faith.

“If it doesn’t isolate him from liability, it comes very close… Even if this statement is false, it’s unlikely a jury would find he was trying to malign them," Berlik said.

Moreover, trevely’s review of Medialink contained a claim saying, “It’s very likely that they are paying for reviews.” Berlik explained that because trevely’s claim is one of opinion that he thinks to be “very likely” rather than a statement of fact, this statement should also not likely constitute defamation.

Scare tactics

Whether or not the law is on trevely’s side, the cease-and-desist letter was a pretty clear scare tactic, according to free speech attorney Paul Alan Levy with the Public Citizen Litigation Group. “The letter was so over the top that you have to think the lawyers were going out of their way to look like they’re filing a lawsuit,” Levy told Ars.

Levy noted that reviewers are safest when they “stick to the facts,” even if the review is negative.

What's more, Levy said, if online reviewers want to protect themselves from paying out-of-pocket expenses related to a defamation suit, they should consider purchasing homeowner's insurance. “If people are going to be active online, they ought to have libel coverage, which is a rider to a homeowner’s policy,” he said. “Generally speaking, an umbrella policy includes personal injury, and most policies do have defamation coverage.”

It might seem strange to need insurance before writing an online review, but consider this: if Mediabridge decides to follow through with its suit against trevely, and even if trevely prevails, he's still responsible for his own legal fees.

“Companies can bully consumers into taking down negative reviews," Berlik said, "since most people don’t want to get involved in a big lawsuit. So consumers are hurt by that."