Psychologists in the United States say that the bullying of teenagers online is common and almost three in four teenagers say they were bullied online at least once during a recent 12-month period.
However the team at the University of California, Los Angeles (UCLA ) say only one in 10 reported such cyber-bullying to parents or other adults.
According to the UCLA psychologists, of those who were bullied online, 85% have also been bullied at school - the psychologists say the probability of getting bullied online was substantially higher for those who had been the victims of school bullying and affects millions of students.
Lead researcher and psychology professor Jaana Juvonen says bullying on the Internet appears similar to what children do face-to-face in school and the Internet is not functioning as a separate environment but is connected with the social lives of children in school.
Professor Juvonen says their findings suggest that cyber-bullying is a common experience, especially among heavy users of the Internet and online and in-school bullying are more alike than different.
The study is based on an anonymous Web-based survey of 1,454 participants between the ages of 12 and 17, who were recruited through a nationally popular teen website from August through October 2005.
41% of the teenagers surveyed reported between one and three online bullying incidents over the course of a year, 13% reported four to six incidents and 19% reported seven or more incidents.
Professor Juvonen says many teenagers do not realise how many of their peers are being bullied online and think cyber-bullying happens much more to them than to others, and when they start thinking it is just happening to them, they are more likely to blame themselves, which increases their risk of depression.
Juvonen says children know how common cyber-bullying is, even among their best friends and it is not a plight of a few problematic children but a shared experience.
The most common reason so few teenagers tell their parents about being bullied online was that teens believe they "need to learn to deal with it", in addition, 31% do not tell for fear their Internet access might be then restricted by parents.
This concern was especially common among girls between the ages of 12 and 14, with 46% fearing restrictions, compared with 27% of boys in the same age group.
One-third of 12-to-14-year-olds reported that they didn't tell an adult out of fear that they could get into trouble with their parents.
Juvonen says many parents have little understanding of their children's Internet use or how vital it is to their social lives and detrimental action by parents with good intentions, is not likely to help parent-teen relationships or the social lives of their children.
Professor Juvonen says children are mainly using the Internet to maintain relationships and connections with their friends.
73% of the participants who reported being cyber-bullied said they knew, or were pretty sure they knew, who was doing the bullying which is counter to the prevalent myth that cyber-bullying is anonymous, says Juvonen.
Neither does the research support the assumption that the Internet is dramatically changing the nature of bullying, as of those participants who experienced bullying, 51% said the bullying was done by schoolmates, 43% said they were bullied by someone they knew only online and 20% said they were bullied by someone they knew, but who was not from school.
The most prevalent forms of bullying online and in school involved name-calling or insults, then password theft; bullying also includes threats, sending embarrassing pictures, sharing private information without permission and spreading nasty rumours.
The researchers say both in-school and online bullying experiences were independently associated with increased social anxiety.
Professor Juvonen says electronic communication devices are not the cause of problem behaviour among teenagers but rather the tools that can be used to interact with peers in both antisocial and healthy ways and she suggest that parents and other adults may overestimate the risk of bullying online and downplay the risk of bullying in school.