I clearly remember the horrible experience of being bullied and humiliated as a pupil in one of the many schools I attended. Thankfully, my humiliation was witnessed by a small number of people and was not shared on the worldwide web or over Bluetooth. Recent publicity exalted the fact that social networking site Facebook now has 500 million subscribers after only six years in business.

This announcement was closely followed by an article about a teenager who had committed suicide following vicious personal comments he had received on Facebook. It seems this young man could not bear such public humiliation and took his own life.

Like most new technology, social networking sites have huge plus points but also new, unanticipated problems. Most schools and parents will be aware that such sites are a new vehicle for bullying and harassment and are very difficult to deal with. However, a social network by its very nature is going to expose the fact that some people “fit in” and others are socially excluded.

Most of us will have been on both sides of the divide at some point of our life according to our social circle at the time, but the difference now is that this is now in the public domain.

If your friends want to put you down in the most vile manner, they can now do it on Facebook or YouTube so everybody can witness your shame. Humiliation knows no bounds. And it seems that for some, other people’s humiliation is simply entertainment.

We all know that young people fall in and out of friendships very easily and we also know that they say some terrible things to each other which are later forgotten. Nowadays it appears in print or on a photo or video and is published so it can never be taken back. The damage is done and is out there.

Our school is not alone in having to deal with a host of issues that have been instigated on Facebook or YouTube. These sites are used to spread gossip, rumours and to arrange illicit parties, fights and other antisocial behaviours. Even more seriously they have been used to bully and harass other pupils. This is also in primary schools.

After uncovering numerous incidents of bullying and harassment through Facebook I felt it important to write to parents to warn them about the dangers. The fact that these incidents were not happening in school was not an issue. We had to cope with the fall-out after the event and so had to accept our share of responsibility in trying to resolve the problems.

It was really sad when a father came to tell me how his daughter has been set up for a “date” on Facebook only to discover it was all a big joke on her. Neither he nor I could see how this was funny and the damage done to the self-esteem of the girl in question is not measurable.

Parents often tell me that they are delighted that their child spends so much time in their room working on their computer, yet these same children often manage to make little or no progress with their learning.

When I point out that their child is very unlikely to be doing work but rather chatting to their friends, or on Facebook or MSN, they seem surprised but often accept no responsibility for their lack of supervision. I wonder if this is because so many parents are also addicted to social networking sites, and many spend hours chatting to their friends when they should be supervising their children?

In fact, some even join in with conversations started by young people. Following a serious incident one weekend involving some of our pupils, we searched Facebook to see what information we could find. We were shocked to find that some of the parents were spreading the gossip and rumours. Where will it all end?

However, it’s not all bad. I was made aware of the benefits of social networking sites when I was stranded in New York after Easter due to the ash cloud. My colleagues who were with me were able to use Facebook to plan lessons, and share information about pupil progress and about the needs of targeted pupils, as well as planning revision sessions and sorting out staff appointments in their department. They were also able to keep in touch with family and friends through Facebook. Of course, I was able to do the same things using email - it just took a little more time!

I know social networking sites are here to stay in school and we need to educate pupils and parents in using such sites sensibly. We will continue to run workshops for parents, even when they are poorly attended. More importantly, we must continue with our anti-bullying work and to make sure that we teach pupils how to resolve conflict and be aware of the consequences of their actions.

So far I have resisted the temptation to sign up on one of these social networking sites, so perhaps I just don’t know what I am missing.

Kenny Frederick, Headteacher, George Green’s School, Tower Hamlets, London.