• by Wendy Davis  @wendyndavis, March 6, 2009

Chicago sheriff Thomas Dart has sued listings site Craigslist for allegedly creating a public nuisance by facilitating prostitution. But Internet law experts say the court will almost certainly dismiss the case because federal law immunizes sites like Craigslist from lawsuits based on material posted by users. 

In a lawsuit filed in U.S. District Court for the northern district of Illinois on Thursday, the Cook County sheriff alleged that Craigslist "knowingly and intentionally facilitates prostitution" through its erotic services ads.

"Craigslist is not limited to innocuous postings selling sofas and advertising apartments," the lawsuit states. "Craigslist has an erotic services section where people openly promise sex for money."

The lawsuit alleges that the term erotic services "speaks for itself." "'Erotic' is defined as 'satisfying sexual desire,'" the lawsuit says, citing Random House Webster's Dictionary. "'Services' is defined as 'the act of doing something useful for a person or company for a fee,'" it continues, quoting from Black's Law Dictionary.

But Craigslist itself gives a different description of "erotic services" on its site. In its FAQ about the category, the site states that the ads are for services like "sensual massage, adult web cams, phone sex, erotic dancing, adult websites, nude housecleaning, etc."

Cyberlawyers predict that Dart will have a hard time prevailing because Section 230 of the Communications Decency Act states that publishers are immune from state tort lawsuits based on material posted by users.

"Craigslist will have a very strong argument that Section 230 preempts the case," said Matt Zimmerman, an attorney with the digital rights group Electronic Frontier Foundation.

In fact, the Seventh Circuit Court of Appeals, which covers Chicago, has already ruled that Craigslist is immune from the suit under that law. In that case, the appeals court dismissed a lawsuit seeking to hold Craigslist liable for discriminatory housing ads placed by users.

Dart is asking for the court to issue an injunction against the site and monetary damages. The lawsuit alleges that the county monitored the site and made 156 arrests, at a cost of around $105,000.

But some observers question the logic of the sheriff's decision to try to recover money, because investigating prostitution would likely have been more difficult, and costly, if suspects had not advertised online.

"When people advertise, you, as law enforcement, have a leg up," said Eric Goldman, director of the High Tech Law Institute at Santa Clara University. "How much does it cost to do the forensics if you don't have people online saying, 'Arrest me, please,'" he told Online Media Daily.

In a blog post about the case, he called the lawsuit "little more than a sad publicity stunt by the sheriff's office."

Last November, Craigslist forged a deal with 40 state attorneys general to charge a small amount for erotic services ads, and also require that advertisers provide credit card information. The site donates those ad fees to charity.

A spokesperson for Craigslist said: "Misuse of craigslist to facilitate criminal activity is unacceptable, and we continue to work diligently to prevent it. Misuse of the site is exceptionally rare compared to how much the site is used for legal purposes."