Angered by what she thought was shoddy work on her home, Fairfax resident Jane Perez did what has become the go-to form of retail vengeance in the Internet age: She logged on to Yelp and posted scathing reviews of the D.C. firm that did the job.

Perez ticked off a list of accusations, including damage to her home, an invoice for work the contractor did not perform and jewelry that disappeared. She closed one post by fuming, “Bottom line do not put yourself through this nightmare of a contractor.”

The contractor’s response to her one-star takedown? Fight back.

Christopher Dietz filed a $750,000 Internet defamation lawsuit against Perez last month, saying the postings on Yelp and others on Angie’s List were false and sent customers fleeing. He is also asking a Fairfax County court for a preliminary injunction to keep her from writing similar reviews. A hearing will be held Wednesday.

Lawyers say it is one of a growing number of defamation lawsuits over online reviews on sites such as Yelp, Angie’s List and Trip­Advisor and over Internet postings in general. They say the freewheeling and acerbic world of Web speech is colliding with the ever-growing importance of online reputations for businesses, doctors, restaurants, even teachers.

It’s snark vs. status.

No one keeps track of how many suits are filed over online reviews, and lawyers say the numbers are still small but are getting larger. Most of the suits fail because juries and the courts have sided with free speech and the rights of the reviewers to express their opinions.

With 84 million visitors a month and 33 million reviews, Yelp especially has become a legal battleground given that the reputations of restaurants, nail salons, dry cleaners and other businesses can be made or shredded in a few keystrokes. For instance, a Chicago plastic surgeon sued after a Yelp reviewer said he gave her “Frankenstein breasts.”

Perez, a retired captain in the armed services, said she never fathomed that her Yelp review could land her in court. It has left her reeling and potentially facing thousands of dollars in legal bills to defend herself.

“I don’t want to see what happened to me happen to anyone else,” Perez said.

Nevertheless, she stands by her reviews, saying that everything she wrote was truthful about the work Dietz did on the townhouse, where she lives with her dog.

Some reviewers and free-speech advocates, including Perez, see the cases as free-speech issues: They say the lawsuits are heavy-handed attempts to stifle critical — but valuable — consumer information that has forced businesses to be held accountable.

On the other side, business owners such as Dietz say they are forced to take extreme legal measures because the Internet has made defamation that much more damaging. A single false post can live virtually forever on a site and reach millions, causing untold harm.

Lawyers say such cases are a cautionary tale for a new era: Those who feel targeted by defamation on the Web are more likely to file suit, and judges and juries are more likely to take such claims seriously than in years past, raising the legal stakes over vitriolic reviews, nasty blog comments and Facebook feuds.

“As the Internet has matured, more and more people are feeling the sting of negative posts against them, and the public and jurors are getting more educated about the impacts this speech can have,” said Aaron Morris, a lawyer who handles Internet defamation cases.

Dietz said his small seven-year-old design and contracting firm had a good reputation. Two reviews on Yelp give him the highest rating — five stars — and one praises him as showing a “high degree of professionalism.”

But that reputation was devastated by Perez’s reviews, he said. He alleges in the lawsuit that they cost him $300,000 in business. The situation has also taken a toll on him personally.

“The impact has been awful,” Dietz said. “There is no one to protect businesses when people slam their name.”

The Communications Decency Act shields sites such as Yelp from defamation suits over content posted by third parties. And Yelp, like many review sites, says it simply can’t check the veracity of millions of reviews, leaving businesses and the site’s reviewers to sort out messy factual disputes.

A 2011 Harvard study quantified just how big an effect those negative Yelp postings can have: A one-star increase among reviews of Seattle restaurants led to a 5 to 9 percent growth in revenue.

Perez hired Dietz’s company, Dietz Development, when she moved to the area and needed cosmetic work done on her newly purchased Fairfax home, according to the lawsuit. Dietz, a high school friend, was to paint, refinish floors, perform electrical and plumbing work, and do other tasks in June 2011.

But things quickly spiraled out of control, Perez wrote in her Yelp post.

“I was . . . left with damage to my home and work that had to be reaccomplished for thousands more than originally estimated,” Perez wrote. She alleges that Dietz “was the only one with a key” when jewelry disappeared from her home and that he trespassed on her property, prompting her to call the police, among other issues in dispute.

Dietz says that he completed the job, that he did not damage the home, that Perez never paid him and that she demanded that he perform work beyond what was part of their agreement, according to the lawsuit. Perez denies those accusations.

Dietz also says Perez’s comments about the missing jewelry and trespassing amount to false accusations that he committed crimes. County court records show that Dietz has not been charged on either accusation.

In Virginia, someone can be found liable for defamation if he states or implies a false factual statement about a person or business that causes harm to the subject’s reputation. Opinions are generally protected by the First Amendment.

Lawyers say such lawsuits are on the rise because of the explosion in popularity of review sites such as Yelp. They also say that commentators are unfamiliar with what constitutes defamation and that others are lulled into a false sense of security online.

“There is a right to speak anony­mously on the Internet,” said Lee Berlik, a Reston lawyer who handles Internet defamation cases. “Armed with that right, I think people feel safe when they are sitting in their pajamas at their desks at home. They feel they have the right to say whatever they want.”

But that right does not extend to defamatory speech. Lawyers across the country are more aggressively using a combination of legal maneuvers and computer forensics to help uncover the identities of anonymous commentators and sue them.

And some of those cases are producing astronomical awards. This year, an Anaheim, Calif., technology company won a $1.6 million judgment against a blogger who had accused the company of stealing money from business associates. And in 2006, a Florida woman won a $11.3 million judgment after a Louisiana woman called her a “crook” and a “con artist” in an Internet forum.

Lawyers say businesses suing reviewers have met with less success. In fact, many such lawsuits have backfired. Some have generated negative publicity for the plaintiffs and have been looked at skeptically by courts.

Last year, a California judge ordered a dentist to pay the legal bills of the parents of a patient he sued for defamation over a negative review one of them posted on Yelp.

Mark Goldowitz, founder of the Public Participation Project, which monitors such lawsuits, said he sees a troubling trend in review site defamation cases such as the one in Fairfax. He thinks they are a threat to vibrant new communities that have sprung up around Yelp and other sites.

“The suits can have a chilling effect on people’s willingness to share information,” Goldowitz said. “It does lead to people not posting reviews for fear of getting sued and to taking them down when threatened by a lawsuit.”

His group is pushing for a federal law that allows defendants to seek early dismissal of lawsuits that are aimed at silencing voices on public issues. Twenty-seven states, including Maryland, and the District have such “anti-SLAPP” laws, but not Virginia, according to Public Participation Project.

Perez has removed her reviews from Yelp, her attorney said, because allegedly false comments Dietz made about her in his response post on Yelp were popping up as the first listing in Google searches on her name.

Berlik, the lawyer, has a few words of advice for those who want to avoid similar lawsuits: Stick to opinion and “tell the truth, and you won’t get into trouble.”