"Don't talk to strangers in public." "Don't open the door to someone you don't know." "Don't give out personal information to someone who calls on the phone."

"Don't talk to strangers in public." "Don't open the door to someone you don't know." "Don't give out personal information to someone who calls on the phone."

Kids learn these real-world rules as soon as they can walk and talk. Most parents want to extend the same kind of common sense rules to the Internet, but it can get awfully complicated: What spaces are "public?" Who is a "stranger?" What kind of "information" makes children vulnerable?

Social networking sites like Facebook were supposed to make the Internet a little safer by creating a community of people who know each other, but it hasn't quite worked out that way. According to Ryan Naraine, a security expert from Kaspersky Labs, these sites create "a faade of trust where end-users feel comfortable enough within their network to click on every link they receive and post the most intimate details of their lives." In his white paper called Friend or Fraud, he points out that the comfort level many people feel on social networking sites makes it very easy for criminals to "manipulate these trusted networks for malicious purposes."

The best way to protect kids is to teach them to protect themselves. That isn't really feasible for children under 13 who simply aren't mature enough to make good decisions about whom to trust.

Their online interactions should be limited to virtual playground sites like Poptropica.com where they can "chat" without revealing personal information, or security-enhanced networking sites like My Secret Circle, which requires a USB device to be uploaded before kids can have access.

Once a teen seems mature enough for social networking, talk often about the risks. Most teens won't respond well to lectures or scare tactics. Instead, help your child develop the online equivalent of street smarts so he or she can spot scams and predators. Here are things you'll want to stress:

Set privacy controls and recognize the limits.
Every social networking site gives members choices about who can see their personal pages. (Find links to privacy pages for several social networking sites at http://kids.getnetwise.org/safetyguide/technology/socialnetworking). Teen-agers should use the most secure settings so no one can see their pages without approval.

Even with that protection, young people should be wary about what they post, especially if they have large networks. Friends may show the page to others who may harvest the kind of details that make it very easy to commit real-life crimes, including identity theft. Encourage your child to think about how a criminal might make use of posted information: This family will be on vacation at Christmastime ... They live on Main Street ... This girl drives home from soccer every night at 7:30; and so on.

Design strong passwords and change them regularly.
A criminal - or bully - who figures out your child's password not only has access to personal information, but also can impersonate your child or use the account to make mischief. Encourage your teen to create powerful passwords that include random letters as well as some numbers and a punctuation mark or two. To create a memorable password, try translating lyrics from a favorite song into code: "Sometimes love comes around and knocks you down" might become slca&kud. Then - and this is important - tell your teen not to share the password with anyone!

Avoid links and pop-ups.
Part of the fun of social networking is passing around links to videos, photos and other cool stuff. Criminals have exploited this enthusiasm with attacks like Koobface (an anagram of Facebook). Victims of this and other attacks get a message from someone they know that includes a link. Clicking on the link downloads "badware" that gives other people access to the computer and, potentially, private information.

To outwit scammers, teach your child to roll the mouse over links to reveal the underlying web address. A URL from a legitimate company will start with the name of the company spelled properly. If the name is misspelled or appears later in the URL, the link is a scam. Teens should also avoid clicking on anything that pops up on the screen including "scareware" messages that promise a free scan to protect the computer from viruses. These pop-ups often implant the very programs they promise to eradicate. Instead, be sure your computer is protected with updated anti-virus software from a reputable vendor like Symantic, McCafee or AVG.

Don't assume a message from a friend is really from a friend.
Even if your child is careful not to download viruses, his or her friends may be less conscientious. If a friend's account is compromised, your child may receive fraudulent messages from a screen name they believe they can trust. For example, some criminals send out distress messages claiming to have lost a wallet or passport while traveling. Because they include personal details gleaned from the social networking site, these contacts may seem authentic. Some people have sent money - only to learn later that their real friend was never in danger. Teens should be equally skeptical of too-good-to-be-true offers that appear to come from friends, especially if they involve fees of any kind. Unfortunately, anyone who asks for money online has to be presumed to be a crook until proven otherwise.

Investigate before joining a group.
Teens regularly get invitations to join groups that can range from silly to serious. Although many networking groups are actually communities of like-minded people, some are established simply to harvest information about people who share a common interest. Tell your child to do a little research before joining a group. Who is the administrator? What is the purpose? How will posted information be used?

Every social network (both on and offline) depends on trust, so every social network is vulnerable to people who are willing to exploit the faith of others.

Teaching young people to be skeptical and self-protective makes it more likely they will avoid online criminals and recognize the people who are true friends.