WWW- When News Corp. bought the social-networking Web site MySpace.com last July, the media company got two surprises, one good and one bad.

The good part: The site, where teens and twenty-somethings post pages about themselves and communicate with friends, already was popular, but it suddenly took off. In the last six months of 2005, MySpace’s monthly traffic nearly doubled to 36 million users, making it the eighth-most-visited Web site in January, according to comScore Media Metrix. News Corp. Chairman Rupert Murdoch declared it the centerpiece of his new Internet strategy of attracting a large audience in a bid to bypass portals such as Yahoo Inc. and Microsoft Corp.’s MSN in advertising revenue.

The bad part: MySpace has become the focus of criticism from authorities, teachers and parents that children are exposed to risqué content and are preyed upon by sexual predators who meet them on the site. Such episodes aren’t unique to MySpace, but the site stands out because of its size — 54 million registered users, with about 19% of monthly users under 17, according to comScore.

In response, News Corp. is scrambling to make MySpace a safer place for young people. News Corp. plans to appoint a “safety czar” to oversee the site, launch an education campaign that may include letters to schools and public-service announcements to encourage children not to reveal their contact information. It also is considering limiting access to certain groups, such as “swingers,” to those over 18; blocking search terms that predators could use to locate kids; and encouraging users between 14 and 16 to make their profiles “private,” meaning they can only be viewed by people they already know.

“We’re going to take some pretty dramatic steps to provide industry-leading safety,” says Ross Levinsohn, president of News Corp.’s Fox Interactive Media unit, which includes MySpace.

It is a delicate operation for News Corp. because the media group wants to retain MySpace’s cool factor. Like other Web sites, MySpace owes its success largely to its freewheeling nature. If the site feels too supervised, teenagers could leave in droves. “MySpace was the first one to allow users to customize their pages any way they wanted,” says Parry Aftab, a cybersecurity lawyer who advises MySpace. “That’s why MySpace took off like it did.”

Yet while many teens use MySpace to innocently chat with friends and share music, other MySpace users post sexually explicit photos and list activities such as “swinging” and “spanking” among their interests. The site has so many explicit pictures that Playboy Enterprises Inc. has launched a casting call for a “Girls of MySpace” nude pictorial for an upcoming issue of its magazine. “We’ve done a lot of these types of castings, and this is by far the best response we’ve gotten to date,” says Michael Sprouse, senior vice president of marketing at Playboy. Playboy requires applicants to submit two forms of ID proving they are over 18. MySpace isn’t affiliated with the contest and says it doesn’t endorse it.

Sexual-abuse allegations involving MySpace are increasing. Police in Middletown, Conn., say they are investigating complaints that five men in their 20s posed as teens, contacted female MySpace users as young as 11 and eventually sexually assaulted them.

No one has been charged, “but we feel confident that we are going to get arrests out of it,” says Sgt. Bill McKenna, supervisor of the family-services unit of the Middletown Police Department. “Investigations of this nature just take a long time to get everything right.”

In September, police in Port Washington, N.Y., arrested a 37-year-old man for allegedly molesting a 16-year-old girl he met on MySpace. This month, police in Bristol, Conn., arrested a 21-year-old for having sex with a minor whom he allegedly met on MySpace.

Connecticut Attorney General Richard Blumenthal said earlier this month that his office is investigating whether MySpace is doing enough to protect children from being contacted by predators and from viewing pornography. MySpace Chief Executive Chris DeWolfe and two News Corp. executives have met with Mr. Blumenthal, and while the attorney general says the meeting was encouraging, he says MySpace’s proposals don’t go far enough. “We’re going to be making some counterproposals that are more demanding,” he says.

“It’s a parent’s worst nightmare to have a young person on this Web site dispensing all kinds of information,” says Mr. Blumenthal. “You will not persuade me that they can’t do a better job of it. Right now it’s the Wild West.” Mr. DeWolfe says MySpace is committed to working with Mr. Blumenthal to make the site safe and secure.

MySpace says it has employees who check each photo loaded onto the site, although it says only a few are rejected, because users realize explicit material will be kicked out. Instead, MySpace says users often add a link to racy photos stored on other sites, such as PhotoBucket.com and ImageShack.us. PhotoBucket.com Chief Executive Alex Welch says his site is beefing up its photo-scanning capabilities so it can scan all the images and kick out explicit photos. ImageShack.us says it already scans all photos that are uploaded to its site to check for porn. MySpace competitor Facebook.com doesn’t allow photos linked to image-hosting sites.

MySpace used to block access to those who said they were under the age of 16. But so many lied about their ages that MySpace lowered the age limit to 14 — and blocked certain communication features for users between the ages of 14 and 16. The company says it has a computer program that checks for clues that users might be lying about their age and has removed 200,000 profiles as a result. Like other sites, MySpace doesn’t verify users’ ages. “No one on the Internet with a free site has ever come up with a way to do that,” Mr. DeWolfe says.

MySpace is also contending with backlash from advertisers, schools and parents. Some advertisers feel leery about the site — even though it reaches the much-coveted youth demographic. Some executives at large ad-buying shops such as Interpublic Group of Cos.’ Universal McCann and Omnicom Group Inc.’s OMD have been discussing whether to advise clients to pull back from MySpace, according to people familiar with the discussions.

At Universal McCann, discussions have centered on whether the firm can set up “quicker than normal” cancellation clauses for ad contracts in case a troublesome situation arises, according to one of the people. Typical cancellation clauses call for two weeks, and Universal is discussing whether the period should be two or three days, this person says. News Corp. says it hasn’t received cancellations or negative feedback from advertisers.

Middletown High School, like other high schools and colleges, blocks its students’ access to MySpace from school computers and plans a workshop for parents on how to manage their children’s access to MySpace.

More parents are taking the initiative themselves. Bellrose, N.Y., resident Connie Couvertier recently shut down her 12-year-old daughter’s MySpace profile and access to the site. Although her daughter’s profile was an innocent listing of her interests and friends, Mrs. Couvertier says she was shocked by the other risqué profiles and photographs. Says her husband, Augustine: “It’s just a sexually charged atmosphere that is inappropriate for young kids.”