By Angela Harrison
BBC News education reporter
Prof Byron says school networks can help parents engage with their children's learning
Many children are social networking without their parents' knowledge, the government's internet safety czar, Professor Tanya Byron, has said.
The child psychologist says there is a "massive mismatch" between parents' opinions of what their children do online and what they really do.
"Parents are often in the dark, so who is talking to kids about what they do?" she told the BBC News website.
Most parents surveyed on Netmums did not let their children social network.
Among 1,741 readers of the site who took part in an online survey, nine out of 10 said their children were not allowed on traditional social networking sites.
Lying about age
However, this is probably partly explained by the demographics of the website's readers - a majority of their children are aged seven and under.
Even so, studies suggest that ever-younger children are lying about their age to get online on sites such as Bebo and Facebook to talk to friends and share photos and other media.
Prof Byron, who carried out a review for the Westminster government into children's safety in the digital world, said: "There are plenty of children going on social networking sites to catch up with friends, having lied about their age - and they are in a playground with adults, not being sensible about their privacy."
One of the answers, she believes, is the setting up of safe sites by primary schools - where pupils can do homework and contact teachers but also chat to friends.
More and more schools have systems children can access in and out of school
Many schools now have computer systems - known as learning platforms - where parents and children can log on to school networks to access homework, information and in some cases monitored social networking sites.
The idea is that children can communicate with each other with less danger that online predators will try to befriend them, and that cases of cyber-bullying can be dealt with by the school.
'Typing mean things'
Prof Byron, speaking at the launch of a social network designed for schools called Kwercus, says school networks are an ideal place for younger children to enjoy talking to their friends - but also to learn how to handle themselves on social networks.
"It helps children with their learning, they can hand their homework in, parents can engage in their learning, which leads to better outcomes," she said.
"But it also has what children love about social networks - but in a safe, secure environment, where people can help them understand that it is very easy to type mean things about someone but it hurts."
Using such networks could help parents educate their children about online risks - and do something to bridge the digital generation gap, Prof Byron believes.
"There are opportunities and benefits with the internet and there is digital hatred. For parents who have not grown up with technology, it can be very difficult."
The government wants all secondary schools to have intranets or learning platforms by 2010, and all primary schools by 2012.
Two schools which make full use of learning platforms and other digital technology have just received awards from Becta, the agency charged by the government with promoting such technology in schools and colleges.
Inner-city comprehensive Broadgreen International School in Liverpool was named alongside independent Prospect House School in Putney, London, as the top two schools in the UK for use of technology.
At Broadgreen, assistant head teacher Peter Banks says the school's vision for ICT is for personalised learning - everywhere and at any time.
"The school wants to make the use of ICT inside and outside school as available and as commonplace as pens and pencils are today," he said.
The school also uses technology to link up with people in the local community.
It has "silver surfers' groups" for older members of the community learning to use technology.
Les, an original member of the group who is 89, regularly communicates via webcam and has his own blog about his war time experiences, Mr Banks says.
Prospect House uses a learning platform called Studywiz, which it says has increased parental involvement in pupils' learning.
The school podcasts lessons on the system so parents can see how methods such as long division are taught. Pupils are encouraged to download lessons on to hand held mobile devices so they can revise anywhere.
Becta's chief executive, Stephen Crowne, said: "We believe that integrating technology across the entire curriculum - not just using it in ICT lessons - is essential to higher achievement in schools and it makes lessons and learning more enjoyable and rewarding."
The winning schools were "shining examples" of what could be done, he added.
The online survey was carried out by Kwercus on the Netmums website.