Now risks are increasingly virtual. And avoidance is almost impossible.

The fastest-growing threat to children may be online bullying.

Of course, bullying has always existed. But social networks have enhanced what bullies can accomplish by adding elements of anonymity, public shaming and blackmail.

Thanks to social networks, bullying is no longer confined to the schoolyard; victims are potentially subject to harassment anytime, anywhere.

Facebook is the best bullying enabler ever invented, albeit an unintentional one.