Social networking sites are a great way to stay in contact with friends and family, and are a way for people to vent about companies they feel are unethical or have poor service. A recent trend, has companies scouring these sites as an inexpensive way of finding unhappy customers and improving customer service. One man in Michigan has found that venting your frustrations on Facebook is also a great way to get sued.

After Justin Kurtz, a college student in Kalamazoo, Mich., had his car towed from his apartment complex parking lot, despite his permit, he decided to create a Facebook page called "Kalamazoo Residents against T&J Towing.” Within two days, 800 people had joined the group, some posting comments about their own experiences with the company. T&J filed a defamation suit against Mr. Kurtz, seeking $750,000 in damages, claiming the site was hurting business.

Legal experts say the soaring popularity of such sites has given rise to more cases like Mr. Kurtz’s, in which a business sues an individual for posting critical comments online. Comment that are potentially permanent records in which businesses have a greater incentive to remove the negative review than the reviewer has in writing the review. Some First Amendment lawyers see the case differently. They consider the lawsuit as an example of a decades-old legal maneuver known as a strategic lawsuit against public participation (SLAPP).

SLAPP is a lawsuit intended to censor, intimidate and silence critics by burdening them with the cost of legal fees until they abandon their criticism or opposition. The plaintiff does not normally expect to win the lawsuit, but hopes the defendant succumbs to fear, intimidation, mounting legal costs or simple exhaustion. A SLAPP also hopes to intimidate others from participating in the debate.

Many states have anti-Slapp laws, and Congress is considering legislation to make it harder to file such a suit. The bill, sponsored by Representatives Steve Cohen of Tennessee and Charlie Gonzalez of Texas, would create a federal anti-Slapp law, modeled largely on California’s statute. Under the proposed federal law, if a case is dismissed for being a Slapp, the plaintiff would have to pay the defendant’s legal fees. Fees that could easily wipe out the average person’s savings before the case is even half done.

In Michigan, which does not have an anti-Slapp measure, Mr. Kurtz’s legal battle has made him a local celebrity. His Facebook page has now grown to more than 12,000 members. On April 30, Mr. Kurtz and his lawyers asked a judge to dismiss the suit by T&J, which has received a failing grade from the local Better Business Bureau for complaints over towing legally parked cars. Mr. Kurtz is also counter suing, claiming that T&J is abusing the legal process. “There’s no reason I should have to shut up because some guy doesn’t want his dirty laundry out,” Mr. Kurtz said. “It’s the power of the Internet, man.”