MySpace.com faces a new round of lawsuits filed in January alleging that it failed to protect minors. Experts say the cases will enter murky legal territory.

Four families whose underage daughters were sexually assaulted after meeting men in person whom they had met online via MySpace filed separate lawsuits in Los Angeles Superior Court. Their lawyers contend MySpace waited too long to employ security measures to protect underage users.

MySpace, owned by News Corporation, has upgraded its security features after facing criticism that predators could use the site to target children. The lawsuits were filed the same week that MySpace said it would release software, called Zephyr, for parents to monitor changes in their children’s accounts.

Some of the issues facing MySpace have also confronted operators of chat rooms and message boards. Yahoo pulled some user-created chat rooms in June 2005 after it found content that violated its terms of use.

Social networking sites, like message boards, aren’t bound by law in how they should operate or what security features they must have, says Struan Robertson, senior associate attorney at Pinsent Masons, a U.K. law firm that deals with technology issues.

Illegal activity is banned in terms of use agreements, but it’s up to the sites to determine how to prevent it.

The lawsuits against MySpace pose legal challenges given a lack of previous cases, says Evan D. Brown, an IT attorney with Hinshaw and Culbertson in Chicago.

At least two U.S. cases suggest MySpace could be in the clear. In February, a federal court in Texas dismissed a similar suit filed against MySpace by a teenage girl’s family, after she was assaulted by a man she met via MySpace: The judge ruled that the company was protected by the Communications Decency Act of 1996. Also, in 2001, Florida’s Supreme Court rejected a negligence suit where a mother alleged AOL failed to close the account of a subscriber who used a chat room to sell obscene photos of her son.