As the government launches a web safety code, Rory Cellan-Jones reports from an internet class at a primary school in Ealing, London.
Lessons in using the internet safely are set to become a compulsory part of the curriculum for primary schoolchildren in England from 2011.
The lessons are one element of a new government strategy being unveiled called "Click Clever, Click Safe".
Children will also be encouraged to follow an online "Green Cross Code" and block and report inappropriate content.
The measures have been drawn up by the UK Council on Child Internet Safety, a new body comprising 140 organisations.
Holden Lane School in Stoke has produced a video for School Report on how a filter system blocks sites
"We must ensure that this virtual world is safe for our children just as we try to ensure that the real world is," said Prime Minister Gordon Brown at the launch of the campaign.
"The internet is a wonderful and powerful tool that is changing the way we learn and the way we stay in touch," he added, "but unfortunately there are risks from those intent on exploiting its benefits."
The "Zip it, Block it, Flag it" campaign is intended for use by schools, retailers and social networks, although it will be up to individual sites to choose how they use it.
A large scale public information campaign based around the slogan will be mounted from February 2010.
"We hope that 'Zip it, Block it, Flag it' will become as familiar to this generation as 'Stop, Look and Listen' was to the last," said the Prime Minister.
It will encourage children to not give out personal information on the web, block unwanted messages on social networks and report any inappropriate behaviour to the appropriate bodies, which may include the website, teachers or even police.
"The digital code is the green cross code for the digital age," said Dr Tanya Byron, who headed a review into inappropriate material on the internet and in video games.
"Its about what the risks are in the online space," she said. "What can be done in order to help them learn to manage those risks and to get help if they become more than they can sort out themselves."
Government-appointed psychologist Tanya Byron on the new child safety online code
The Byron review saw the creation of the UK Council for Child Internet Safety (UKCCIS) which has drawn up the digital code.
"No one is saying it is scary stuff," said Dr Byron. "It's about the management of risk in the same way that we want children to understand and manage risk in the real world, in the offline world."
"No-one is saying there are huge massive dangers out there," said Dr Byron.
"18% of children have said they have come across inappropriate material," she said. "Its 18% too many but it's not as big as people believe based on the scare stories and fear-mongering."
UKCCIS comprises organisations including Google, Microsoft and Facebook, which have pledged support for the campaign.
A Google spokesman said most of the websites represented by the group already had controls that "help users manage their personal information and block or report unwanted contact".
The curriculum is already massively overstretched. It's difficult for teachers to fit everything in
"We're strong supporters of the 'Zip it, Block it, Flag it' educational campaign as another way to get this message out and help young people to remember how to stay safe online."
The 140 organisations are also updating a self-regulatory code of conduct governing online behaviour.
The rules will be published in 2010 and will act as a benchmark against which the government can review websites.
One measure that has been discussed by the group is the use of a "panic button" on social network sites to flag up inappropriate content.
The Child Exploitation and Online Protection (Ceop) centre - the UK law enforcement agency tasked with tracing online sex offenders - already offers a report button for websites.
Clicking the button allows users to contact specially-trained Ceop officers for advice and Ceop says it receives 10,000 hits a month.
It is already used by social network Bebo and MSN Instant Messenger but the government will announce that all 270,000 computers provided under its Home Access scheme will now incorporate the button.
A critical part of the government's plans are educating children about the potential dangers they face online.
Currently only secondary school pupils are taught about internet safety.
Under the new proposals, online safety would be taught to all pupils from the age of five in England as part of their personal, social, health and economic education (PSHE), which includes drug awareness, bullying, sex education, healthy living and personal finance.
WHAT IS PSHE?
Personal, social, health and economic education
Topics include: alcohol, drug and tobacco awareness; bullying; sex and relationship education; sexuality; careers advice; personal finance; healthy living; body image and how the body changes; personal well-being
Taught in age-appropriate ways in both primary and secondary school
The government wants the subject to be compulsory from 2011
Teaching PSHE is not currently compulsory, but if legislation goes through it will become compulsory in England from 2011.
However, Anastasia de Waal, of think tank Civitas, questioned whether the measures would have much of an impact.
"The curriculum is already massively overstretched," she told BBC News. "It's difficult for teachers to fit everything in."
As a result, she said, teachers would "cover a lot with not much depth".
She said, it would be much better for teachers to talk about everyday situations, including websites, rather than teaching it in isolation.
Social networks and web services are coming under increasing pressure to show that they are doing something to tackle inappropriate content, cyber-bullying and grooming online.
In November, a poll of more than 2,000 young people by charity Beatbullying found that 57% had been harassed online while using Windows Live Messenger.
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