Millions of young Britons are putting themselves at the risk of identity fraud by leaving their "electronic footprint" on Internet Web sites and blogs, the country's privacy watchdog warned on Friday.
Concerned about the explosion of personal information available online, the Information Commissioner's Office (IOC) has launched official guidelines for millions of people who use networking sites such as Facebook, MySpace and Bebo.
The guidance includes warnings that a "blog is for life" and "reputation is everything" while entries can leave a permanent "electronic footprint" on the Internet.
The report said that the future of almost three-quarters of young people aged between 14 and 21 - about 4.5 million people - could be placed at risk by the reckless use of information. The IOC survey found the online content "could damage the prospects of young people and leave many more vulnerable to identity fraud".
The warnings come in a week that the government said computer discs containing personal information, such as bank account details, of 25 million people had been lost in the mail, putting them at risk of identity fraud.
The survey said that almost two-thirds of young people post their date of birth, a quarter list their job title and almost one in 10 give their home address on their profiles.
The report found that about a third of all young people never read privacy policies and "don't understand how they can manage their personal information", said the IOC deputy commissioner, David Smith.
"Many young people are posting content online without thinking about the electronic footprint they leave behind," Smith said in a statement.
"The cost to a person's future can be very high if something undesirable is found by the increasing number of education institutions and employers using the internet as a tool to vet potential students or employees."
Smith said that about 95 percent of the survey's respondents were "worried" about the implications of the use of personal information on the Internet.
Almost three quarters of youngsters said they did not want any potential employers scouring their social networking profiles, despite their lack of awareness.