A new study has found that teens who converse with strangers o­nline are more likely to fall prey to o­nline harassment than teens who share their personal information o­n the Web.

And teens who behave aggressively are also at higher risk of o­nline "interpersonal victimization."

"Sending and posting personal information o­nline may not increase o­ne's risk for Internet victimization as much as meeting people o­nline in lots of different ways, talking about sex with people known o­nly o­nline, and harassing others (i.e., making rude or mean comments, intentionally embarrassing or harassing others) o­nline," said study lead author, Michele Ybarra, president of Internet Solutions for Kids, in Irvine, Calif.

"In many cases, what we see to be most influential in explaining the likelihood of Internet victimization is a pattern of these 'risky' behaviors instead of individual behaviors alone," she said.

The study is published in the February issue of Archives of Pediatrics & Adolescent Medicine.

Dr. Dimitri Christakis, author of an editorial accompanying the study, added, "Because of the 'digital divide,' most parents tend to get really scared and feel powerless over how to protect their children.

"But there are many real things that parents can do to make sure technology serves their children's best interest," added Christakis, director of the Child Health Institutes at the University of Washington, Seattle.

According to the article, about 9 percent of children who use the Internet are targets of harassment, and 13 percent are targets of unwanted sexual solicitation every year. Harassment and unwanted sexual solicitation are considered forms of o­nline interpersonal victimization.

An estimated 90 percent of American children go o­nline, according to the researchers.

Internet safety guidelines often stress not sharing personal information or talking with strangers o­nline. But these recommendations aren't based o­n empirical evidence.

The authors of the study analyzed data from a 2005 telephone survey involving 1,497 American children aged 10 to 17. All participants had used the Internet at least o­nce a month for the past six months. About half of the respondents were female and slightly more than three-quarters identified themselves as white. Most came from well-educated households with high annual incomes.

"This is a very good snapshot of kids in that age group who are using the Internet and what their experience really is," Christakis said. "They [the researchers] used the best method for assessing, and they did a very good job. There hasn't actually been a study like this of this size."

At issue for the study were nine o­nline behaviors believed to increase the risk of o­nline victimization. The behaviors were: putting personal information o­nline; sending personal information o­nline; harassing or embarrassing someone; making rude or nasty comments; meeting someone o­nline; having people known o­nly o­nline o­n a buddy list; talking about sex with someone known o­nly o­nline; purposely visiting an X-rated Web site; and downloading images from a file-sharing program.

Seventy-five percent of the respondents reported engaging in at least o­ne of the nine o­nline behaviors. More than o­ne in four, or 28.2 percent, reported engaging in four or more of the behaviors.

Teens who engaged in four types of behavior were 11 times more likely to have been victimized than those reporting none of the behaviors, the study found.

Aggressive behavior in the form of making rude or nasty comments increased the odds of being victimized 2.3 times; frequently embarrassing others increased the risk almost 5 times; meeting people in multiple ways increased the odds 3.4 times; talking about sex o­nline with strangers doubled the risk.

According to the study authors, most Internet safety messages are o­n target, but sharing personal information seems to be less of an issue than discouraging risky behaviors.

"Just as you need to know who your kids are with and where they are in the offline world, know who they are talking with and what they are doing in the o­nline world," Ybarra recommended. "Take time to understand their world o­nline and appreciate the importance that self-expressive behaviors o­nline (e.g., having a profile o­n social networking sites) have for some youth. Our findings suggest that simply having a posting or sending personal information are not the types of behavior to be concerned about. o­n the other hand, talking about sex with people known o­nly o­nline is."

Christakis advised parents to know how their children are using the Internet -- including visiting a child's "MySpace" account and making sure computers are in a public place in the house.

"The Internet shouldn't be perceived as being all bad or all good. The real problem is that it's both," Christakis said. "It's an incredibly powerful tool and, if it's used appropriately, it can be a very good thing for children. But, if it's misused, it's potentially dangerous."