It may surprise you to know that being honest in an online review about your disappointing experience with a product or service could have spelled financial trouble for you.

But freedom of speech is being fully restored to online reviewers, starting tomorrow, when the Consumer Review Fairness Act of 2016 goes into effect.

Some mostly small companies that rely on word of mouth, including home builders, hotels, and even doctors’ offices, had been sneaking in the equivalent of “gag orders” into the fine prints terms and conditions they have you sign when you buy a product or service.

A few even acted on their threats. In one case, the retail website sent a Utah couple a bill for $3,500 after they posted a negative review on, complaining about the company's failure to deliver a desk toy and keychain costing less than $20. A federal court ruled that the couple didn't have to pay after the company failed to appear to answer a lawsuit the couple filed against it. But by that time the couple's credit had already taken a hit.

The company is now under new management and no longer has the clause in its fine print. The former owners could not be reached for comment.

The new law, which had bipartisan support and which President Obama signed late last year, prohibits enforcement of so-called nondisparagement clauses that attempt to penalize customers for posting negative reviews.

Consumers Union, the policy and mobilization arm of Consumer Reports, was an early supporter of the law. “If a business can't or won’t deliver on its promises, it should have to answer in the marketplace,” says George Slover, CU senior policy counsel.

The law applies to fine print that is presented on a take-it-or-leave-it basis, when the consumer has no opportunity to negotiate the terms. These are the kinds of terms and conditions you might encounter when shopping on a website that has you click an “I agree” box before you can complete the transaction.

But just because the restriction is going to be lifted doesn’t mean you can say whatever you want when writing about companies on sites like Yelp, Amazon, or on social media, according to Eric Goldman, a professor at the High Tech Law Institute at the Santa Clara University School of Law in California. “You are still accountable for your words,” he says. If you make false statements that damage a company's reputation, he says, you could be successfully sued for defamation.

And while the truth generally is an absolute defense against defamation claims, defending yourself in court—even against a frivolous lawsuit—can be a big hassle.  "It costs money to find out what the truth is," says Goldman. So while you shouldn't let the fear of lawsuits scare you into silence, he says, you should be careful what you say.

User Review Do's and Don'ts

Here's what you should know when writing online reviews so you don't get into trouble and can defend yourself if you do.

Don't assume you're anonymous. Just because a website allows anonymous online reviews doesn't mean a company can't track you down, using your IP address or other methods, says Goldman. Even if a website's policy is to protect participants' identities, a court order requiring disclosure likely trumps everything.

Do include supportable facts. Don't state facts that you can't prove, such as: "The company charges customers' credit cards without their permission." And be careful about using words like "rip-off," "scam," or "con artist." Goldman advises confining your comments to your personal experiences with a company and avoiding generalizing.

Don't confuse facts and opinion. Opinions generally are protected speech. So go ahead and say that the company's website is difficult to use or that you don't like the color choices for its products. But don't say: "In my opinion the company is defrauding its customers."

Goldman says, "Just putting 'in my opinion' in front of a factual statement doesn't make it an opinion."

Do immediately respond to complaints from a company about a negative comment you made online. If a company contacts you,  reexamine what you said. If you decide you said something incorrect or unsupportable, change or delete your comment immediately and let the company know you've done so, without acknowledging wrongdoing. There's no guarantee that will stop a lawsuit, but it could be enough to satisfy an angry business, says Goldman. "Just as matter of ethics, you should fix your errors," he says.

Do contact an attorney if you're threatened with legal action. You might need a lawyer experienced in libel law. If a company targets you with a frivolous lawsuit, you may be able to recover attorney's fees and, in some cases, damages under state and federal laws. If you're successfully sued, you might be covered by your homeowners or renters insurance, subject to the policy limits, says the Insurance Information Institute. Your insurer also may help you find an attorney, says Goldman.