The $30 million lawsuit accused the site of having no measures to protect children who use it. The lawsuit also named MySpace's parent company, News Corp., and the 19-year-old, whose criminal case has not yet gone to trial.
In a ruling issued Tuesday, U.S. District Judge Sam Sparks said MySpace is protected under the Communications Decency Act and cannot be expected to verify the age of every user because that "would of course stop MySpace's business in its tracks."
The decency act cited by Sparks generally grants immunity to interactive computer services such as MySpace so that they are not liable for content posted by users. Without immunity, companies such as MySpace "would be crippled by lawsuits arising out of third-party communications," Sparks wrote.
An attorney for the girl and her family said they will file an appeal.
"This is allowing sites like MySpace to avoid the responsibility to make the Internet safe for children," Jason Itkin said. "MySpace knows its Web site is a playground for sexual predators. Because of that, MySpace should be doing some very basic safety precautions."
In a statement, MySpace officials applauded the judge's decision that the company isn't responsible for "wrongdoing committed by individuals who visit our site."
The lawsuit was brought by the Austin girl, who alleges that Pete Solis, of Buda, lied in his MySpace profile about being a high school senior to gain her trust and phone number. Solis was arrested May 19 on a charge of sexual assault of a child.
MySpace, which has become a lightning rod for warnings about online sexual predators, is a social networking Web site that lets users post photos, blogs and journals. There have been scattered accounts of sexual predators targeting minors they met through the site.
The site has more than 100 million registered users and purports to be the most visited Web site in the United States.