THERE IS a saying that the ostrich, when hiding, buries his head in the sand and believes his whole body to be invisible to the outside world. What a dumb bird. Baffling, really. Yet many of us confidently "put our heads in the sand" every time we get on the Internet.

We somehow believe that we are hidden, invisible--maybe even safe--with our words and our thoughts. Even at this moment, as I type quietly in the solitude of my own home office, it feels incredibly private. And yet just a push of a button could put my personal contemplations and conversations out there where they can be etched permanently into the record of cyberspace.

This illusion of privacy can be a very dangerous thing--especially for youths.

Cyberbullying has taken center stage this week after several recent suicides, including that of 18-year old Tyler Clementi, who was secretly taped in a private interaction with another boy and, upon finding that the video was posted online, committed suicide.

WORD WARFARE

Cyberbullying has been defined as any type of bullying or harassment online. It can include mean comments, sexual harassment, spreading rumors, threatening or aggressive language, even teasing or lying. It can occur in any mode of Internet interaction and even on cell phones.

It is a growing problem. In 2005, the number of youths ages 10 to 17 who indicated they were involved in cyberbullying was twice the number reported five years before that.

I think two normal developmental issues put our teens at great risk for suffering the worst effects of cyberbulling:

First, for a teenager, the opinion of peers is of utmost concern.

Second, teens haven't developed the ability to see very far beyond the present.

Put those two together, and our most useful tool for disseminating information can become a dangerous psychological weapon. In fact, The New York Times last week ran a piece that called cyberbullying "psychological warfare."

UNKNOWN THREATS

As a parent, I know how easy it is to have your head in the sand. When kids are quietly typing at the computer, we parents assume they are doing homework or chatting innocently with a friend.