Did you hear about the one about the Southwest Airline traveler who was an A-list early boarding member but complained on Twitter about “the rudest agent in Denver” when the agent wouldn’t let his two elementary school-age children board the plane early with him? It turns out that Southwest kicked him and his two kids off the flight until he agreed to delete the tweet.

The lesson? Be careful how you complain on social media.

According to a study by VentureBeat, social media users complain on social media 879 million times a year on Facebook, Twitter and other social media platforms. And this vocal minority is growing fast.

Whether people are complaining because their foot-long Subway sandwich is only 11 inches or because a moving company didn’t pay for something they allegedly broke, it’s not surprising that more and more people are turning to social media to get heard.

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Complaints on social media get faster and more satisfactory responses than regular complaints, according to recent marketing studies. But there’s a downside.

Some companies have sued people who tweet or post negative comments for defamation, and some doctors’ offices have banned patients who posted negative reviews of them on Yelp or other online forums. A chef in Cleveland tracked down and texted a series of profane and threatening text messages to a Yelp critic who allegedly “trashed” his restaurant with a bad review. (The chef was particularly irate that the reviewer confused ramen noodles with noodles made from soba or buckwheat.)

So how can you be a critic without finding yourself sued, stalked or booted back to the airline gate as your plane is about to take off?

Jill Bronfman, an adjunct professor of law and data privacy at UC Hastings College of the Law in San Francisco, is convinced you can complain about your cake and eat it, too. She and media consulting expert Kim Beasley have these tips.

Complain politely. The relative anonymity of the Internet may lead you to be more brash online than you are in person. Bronfman says to be careful not to act on that impulse when grousing on Twitter, Facebook, Yelp or other social media. And don’t use profanity or insults, she adds: this can come back to haunt you.

Be reasonable. As fun as it is to vent, realize that many small business owners are working around the clock and the fact that you didn’t get celebrity treatment in an uber-crowded restaurant does not warrant a blistering review. Don’t try to extort favors while letting someone know you are, say, an Elite reviewer for Yelp.

Don’t single out a specific person. Even if an employee has been rude to you, it’s better to keep the complaint general so you don’t raise the stakes. Bronfman believes that was the Southwest flyer’s biggest mistake. “He could have made the complaint public without naming [the reservations clerk],” she notes. The reservations clerk claimed later she felt personally threatened by his tweet.

Never release private or confidential information in social media. Don’t try to get back at your own company about a perceived slight by posting private details about conversations online. “Save that for your private letter,” Bronfman advises.

Make sure your facts are true. “While it is still highly unlikely that a company could or will sue you for defamation, the best defense is the truth,” Bronfman says.

Related: 8 Ways to Protect Yourself on Social Networks

Find the Twitter or Facebook customer service account of the company you’re complaining about, if one exists, and tweet or post to that department. “That way you are showing your good faith,” says Beasley. “You are trying to resolve an issue, rather than just badmouthing the company.”

Take the time to thank the company after it’s helped you, says Beasley. Only about 20 percent of social media complainers do this, she notes.

Talk with your insurance agent about an “umbrella policy” rider on your personal insurance policy if you are very active on social media. “The intent of such a policy is to protect you in the case of libel or slander, among other things” says an agent at State Farm Insurance in northern California who didn’t want to be identified. “But we’re in a whole new area, so check carefully with your carrier” before doing so.

Bronfman says that both customers and business owners are swimming blindly in a new grey area. “We’re caught in the tension between consumer’s First Amendment rights and businesses’ right to their own privacy, their own right to be safe and their right not to conduct business with harassers.”

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Kathryn Olney is a freelance writer and editor who has served as a reporter and editor for California, San Francisco and Mother Jones magazines.