A new advertisement highlights the threat of online bullying
Half of Europe's teenagers browse the web with no parental oversight or supervision, a survey suggests.
The research into the web habits of 20,000 14 to 19-year-olds across Europe found that 51% enjoy unfettered access to any and every website.
The MSN research also found that 29% of the teenagers it quizzed have suffered bullying while using the web.
It comes as the EU marks Safer Internet Day with pledges from 17 social sites to do more to protect younger users.
"We were surprised that it's over 50% without any parental control," said John Mangelaars, head of Microsoft's consumer and online divisions in Europe.
The popularity of social networking sites such as Bebo, MySpace and Facebook among youngsters has helped them become sophisticated web users, said Mr Mangelaars.
"But," he added, "they still need help and guidance on how to tackle emerging issues such as online bullying.
"The findings reveal worrying gaps in their internet education," he said.
A separate survey carried out by the EU Kids Online research project at the London School of Economics found wide national differences in the way parents police net use.
British parents were the most likely, 77%, to use filtering software and to talk to their children about what they do online (87%).
But, found the research, this oversight did not mean that British parents were the most worried about what their children could see online.
French (88%), Portuguese (84%) and Greek (81%) parents were the most concerned about their offspring seeing inappropriate content such as violent images or pornography.
Parents worried about what their children are doing online are encouraged to put a family computer downstairs, maintain an interest in what their children do online and teach children safe habits.
The European Commission marked the sixth Safer Internet Day by unveiling details of an agreement on net safety that many web firms have signed up to.
Under the terms of the agreement the sites, which includes Bebo, Facebook, YouTube, Habbo Hotel and Yahoo! Europe, will take steps to proactively protect younger users.
These include prominent display of a "Report Abuse" button, switching online profiles of those under 18 to private by default, making profiles of those under 18 not searchable and discouraging registrations from those too young to use a site.
Viviane Reding, EU Commissioner for information society and media, said the agreement was "an important step forward towards making our children's clicks on social networking sites safer in Europe."
In a statement she said the potential for social networking sites to flourish should only happen when children have the trust and tools to stay safe while they use such web destinations.
She added: "I will closely monitor the implementation of today's agreement and the Commission will come back to this matter in a year's time."
Safer Internet Day has been marked across Europe since 2004 and this year includes events in more than 50 nations. Many events involve schools that aim to teach children ways of staying safe online.
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