The past few years have seen the introduction of a new area of teenage life where many parents have almost zero knowledge of what's going on - the Internet

Extracted from Teenagers! What Every Parent Has to Know by Rob Parsons

Most of us, as parents, understand the dangers of inappropriate content (such as pornography), and with more and more young people accessing Internet content on their mobile phone, we are quickly recognising the commercial pressures - often having to foot the bills!

The risk that children might come into contact with a stranger who threatens them or seeks to meet up with them to abuse them, is a growing fear which is being amplified by the new phenomenon of social networking.

How social networking works

Sites such as Bebo, MySpace and Teenspot are somewhere where teenagers can swap ideas, gossip and photographs, and drool over X Factor winners away from the prying eyes of adults.

They are all different, but essentially they work like this: you register with your name, address, email and phone number and then fill in a personal profile which will cover things like your favourite music, bands, films and any other interesting bits which will appear on your 'homepage'.

You can design your homepage in your own style, including photographs, and are encouraged to add your school. This can only be viewed by 'selected direct friends'. Bebo suggest that if you are under 21 you do not elect to make this page public - but if you do, the information is open to any other registered user.

The risks

It's not hard to understand how such sites can become popular. Will Gardner, the research and policy manager for Childnet says: 'These sites can be fantastic environments for kids. They can express themselves, talk about their music tastes and what's bothering them, and communicate with each other. What we are concerned about are the potential dangers and risks involved and the lack of awareness some children might have.'

It was these risks that worried Linda Wybar, the head teacher of a girls' school in Kent. More than seven hundred of her pupils have signed up to Bebo, but she called in the police when she discovered that some of them were not only revealing personal details, but posting photographs of themselves on it that she considered 'indecent'.

One 16-year-old girl had submitted a photograph of herself in a swimsuit on her bed and had given enough personal information for a reporter from the Daily Mail to discover her address and phone number within minutes.

A spokesperson for the Child Exploitation and Online Protection Centre, a new Government funded police centre says: 'There is a phenomenal growth in social networking sites, and young people have been putting personal information there which could easily identify them. We don't want them to put that kind of information online - because that's where young people go - so do paedophiles.'

According to police sources more than 50,000 sexual predators are thought to be online at any one time. And of the eight million children in the UK with access to the Internet, one in 12 says they have gone to meet someone whom they initially encountered online.

'Not my teenager!'

It is estimated that over 60 per cent of 13 to 17-year-olds in the UK have personal pages on social networking sites. Of these, 46 per cent claim to have given out personal information, while only five per cent of their parents realised this. A third of them have received unwanted sexual or offensive comments - though again only five per cent of parents had any knowledge of this.

Professor of Social Psychology Sonia Livingstone says to parents: 'Eight per cent of young users who go online at least once a week say they have met face to face with someone they first met on the Internet and 40 per cent say they have pretended about some aspect of themselves online. Parents need to be more aware of the risks their children are facing.'

Here are some steps that can help

• Encourage your child to use a chatroom that requires registration the first time you visit. These are also more likely to have 'moderators' - people who keep an eye on what is going on and have the ability to exclude people who are breaking the rules.
• Explain that even after they have registered, they should never give out their email address or phone number to somebody they do not know.
• Encourage your child to use a nickname and also to be careful not to give out their friends' details.
• Some sites allow children to build up a list of 'selected friends'. These are other users that your children trust and allow to chat with them. Talk with your children about what they might want to be sure of before they invite somebody to join their 'selected friends'.
• Warn your teenager to be aware of somebody who wants to get too close too soon or someone who wants them to send a photograph or use the webcam, or who sends photographs of themselves which make your teenager feel uncomfortable.
• Sending photos is fine - to people your teenagers actually know. But remind them that they should never send their photograph to somebody who is just an 'Internet friend'. Also remind them that when they send a photo via their mobile phone, they are normally sending their mobile phone number as well.
• Tell them to always let you know if somebody has made them feel uneasy - perhaps by inappropriate language or suggestions. Incidents can be reported to your service provider or to the CEOP centre at www.ceop.gov.uk
• Remind your child that they should only meet face to face with somebody they have 'met' online if they have an adult they trust present - and then only in a public place.
• Warn them about chatting online with somebody who is obsessed with secrecy. They may insist you don't tell anyone about their chats with you or ask you to keep details of a proposed meeting secret.
• Having a computer in the living room or somewhere else where people are coming and going makes it a little harder to get into trouble.
• Consider installing filtering software that prevents your teenager entering sites that you don't wish them to.

Extracted from Teenagers! What Every Parent Has to Know by Rob Parsons. Published by Hodder & Stoughton, £7.99.