The vast majority of teenagers using controversial social networking sites such as Bebo make no effort to restrict public access to their personal profiles, according to a new survey.
A majority say they have accepted as "friends" people they do not know but have merely "met" through the internet, the survey of 400 students attending last month's Young Scientists' Exhibition has found.
The findings are likely to raise further concerns about the potential for abuse of social networking sites, which have been the focus of concern over "cyber-bullying" and cases of older men posing as children or teenagers seeking to "groom" young children.
One-half of the teenagers surveyed said that they had experienced or witnessed cyber-bullying, with one in 10 saying this had happened "lots of times".
Almost 70 per cent of teenagers leave their profiles public, meaning that anyone can access the information and, for example, reproduce photographs originally intended for distribution among a group of friends.
Another 13 per cent did not know how to restrict access and only 18 per cent limited information to selected friends.
"But users have to understand that even when their information is marked private, it can still be accessed easily by complete strangers," said Simon Grehan, project officer with the National Centre for Technology in Education. "The combination of 'privacy' and 'internet' is an oxymoron."
While only 8 per cent of young people admitted to posting personal information on their site, 12 per cent displayed their mobile phone number.
"It is difficult to understand why they would bother to do so," said Luison Lassala of Anchor Youth Centre in Artane, which carried out the survey.
One-quarter of teenagers said that they had accepted "loads" of unknown people as "friends" on their sites, and another half said that they had incorporated "very few" strangers into their lists of contacts.
The vast majority said that they used their site to stay in contact with friends, but 13 per cent said they made new friends while 3 per cent said their main purpose for using the site was to contact strangers with no intention of making friendships.
Asked how hard it was to access adult material, one-third said that it was very easy, over 40 per cent said that it was easy and one-quarter described it as hard.
While most social network sites operate minimum age restrictions (13 for Bebo, 14 for MySpace) the survey uncovered a significant number of underage users of these sites (more than 25 per cent).
The survey also shows that Bebo dominates the market for social network sites.
More than 85 per cent of teenage users said that it was the website they visited most regularly, with only 11 per cent preferring YouTube and and 3 per cent opting for MySpace.
Four out of 10 teenagers accessed their favourite site daily, and more than two-thirds visited at least three days a week.
However, the novelty of social networking sites is beginning to wear off, the survey suggests. Just 10 per cent of young people say they spend more than three hours on their site each day, compared to 22 per cent in a similar survey last year.