Is it enough to supervise your children's online activities at home, by setting and enforcing rules such as no chatting, no instant-messaging people you don't know, no filling out registration forms, and no putting personal information on your Web site? Should you also worry about their online safety at school?

Statistically, kids are safer online at school than at home. They are often better supervised at school, as someone usually oversees all their online activities by watching the PCs or using monitoring technology. Also, most children have limited school Internet access; the less time they spend online, the less likely they are to be drawn into something harmful.

Another key factor is the expertise of school librarians and media specialists. One of them told me that you can always tell when students are surfing where they shouldn't be: Other kids gather around to see what's on the screen. It's rarely pornography; more often it's a gory site, or one that targets a student. Librarians can usually find sites that threaten specific children, by watching for high traffic to little-known sites (which kids find by word of mouth).

Many schools block instant messaging and chat. Since most Internet sexual predators entice children through these means, this alone makes your child much safer. Still, make sure that the school and its board have effective policies in place to deal with a variety of cyberrisks.

Ask if the school has an acceptable-use policy. It should be signed both by students and parents, and clearly state the rules, the consequences of violating them, and how to report problems. Find out what happens if a parent refuses to sign; too many schools let the student go online anyway, feeling it's needed for their education.

Ask about privacy. Does the school have a Web site? Does it include the school directory or students' personal information? Student photos? (Pictures should show groups of four or more students and not give their names.) Does the school let students fill out forms online or register at Web sites? COPPA (the Children's Online Privacy Protection Act) bars Web sites from letting preteens use interactive communications (chat, IM, discussion boards, e-mail) or from collecting personally identifiable information from them without parental permission. In cases when a school acts in lieu of a parent in giving consent, are parents informed? Are teachers aware of the regulations?