Writing a bad review is a powerful form of catharsis. You spent money on a good or service and had a negative experience, so you do the only thing you can: try to warn others. Internet denizens have a variety of critical tools at their disposal, from the humble Amazon review section to organized forums like Yelp, to paid communities such as Angie's List. But what happens when the business you're reviewing takes issue with your commentary? Recently, some authors of negative reviews have begun receiving lawsuit threats. One Bad Review Away From a Lawsuit Earlier this month, a man who left a bad review for a Medialink router on Amazon received a letter saying he'd face a defamation lawsuit if he didn't delete the comments. The man posted the letter to Reddit, causing an immediate backlash against Mediabridge Products, the makers of the router. In a statement on the company's Facebook page (which has since been deleted), the company reportedly denied having actually filed a lawsuit against the reviewer but admitted that "Amazon has revoked our selling privileges," according to Ars Technica. It is heartening to see that Amazon would support a customer's right to leave a bad review in this manner. However, there's no denying that another customer may not have been able elicit the same Internet backlash, which likely prompted Amazon's response. Staring down the barrel of litigation, another customer might have been bullied into deleting the review. Unfortunately, online reviews are increasingly becoming the subject of court battles. For example, in January a Virgina court ordered Yelp to reveal the names of seven people who left negative reviews for for a carpet cleaning company. "Consumers may feel the need to speak anonymously for privacy reasons or for fear of unfair retaliation by a business," Yelp said in a statement to CNET. "This ruling also shows the need for strong state and federal legislation to prevent meritless lawsuits aimed solely at stifling free speech." The Truth is On Your Side Ultimately, you have every right to leave a bad review, as long as you act in good faith and don't lie. The difference between a legal negative review and an illegal one comes down to libel in many cases: "While defamation laws can vary depending on the jurisdiction, libel is the defamation of a company or individual in written form," explained TekRevue. "To prevail on a libel claim, the plaintiff must prove that the defendant made a published statement about the plaintiff that was false, injurious, and unprivileged." So what does that mean for reviewers? We're not dispensing legal advice, but everyone knows that honesty is the best policy. Of course, not all reviewers have good intentions. As The Telegraph reported, some British hotels and restaurants claim they've been "blackmailed" by guests "who demand free meals and stays in exchange for not writing bad reviews on the TripAdvisor website." However, knowingly lying in an online review falls under the definition of libel — and that's a lawsuit you'll probably lose. Negative Reviews Can Help Businesses No one wants to deal with with public criticism, but recent research suggests that a few 1-star reviews may actually help a company's reputation. A study published the Journal of Consumer Research "found that polite but negative reviews could improve the way a customer views your products and services," reported Forbes. "Participants even named a brand more honest, down-to-earth, cheerful, and wholesome when there was a polite customer complaint, compared to no complaint at all." There's a lesson here for businesses and consumers: online reviews should be seen as a form of constructive criticism, not revenge. When a customer shares a bad buying experience online, it's a chance for that company to learn from its mistakes. In the worst case scenarios, well-intentioned negative reviews can warn other customers away from bad apples. But if the customer isn't interested in being helpful and instead chooses to lie, then they could face genuine legal trouble. Readers, have you had a bad online review challenged by a company? Or maybe you're a business owner who's been the target of malicious reviewers? Share your perspective in the comments below! Related DealNews Features: Will Your Internet Access And Emails Be Taxed? Get the Facts on a Supreme Court Case That Could Change TV Forever VIDEO: Can You "Like" Away Your Right To Litigation?