As she scrolled down the page Siannii, 13, was shocked to see a picture of herself and the caption: “Well, dis iz da slag Siannii athat no one loikes coz shes a dirty greebo. Plz sign da shout box of wt u think of her xx SHES A SLAGxx.”

Beneath it were dozens of messages, some telling her to “f*** off and die”, while others said: “We’re going to get you at school tomorrow.” The page had been viewed more than 2,000 times.

“It was awful,” said Siannii, from Farnborough in Hampshire. “I was terrified to go to school. I wasn’t sleeping. I began to think that maybe they were right: maybe I should just kill myself.”

Siannii’s is far from a lone case. The past two years have seen an explosion in “social networking” websites where teenagers meet and chat.

The sector is dominated by two players, Myspace and Bebo, which between them boast more than 100m users worldwide. Myspace, recently acquired by News Corporation, owner of The Sunday Times, is by far the bigger and has attracted controversy over child safety issues in the US.

Bebo, however, which was started a year ago, is now level-pegging in the UK with 4m users, and organises its site around individual schools.

Once logged in, teenagers create “home pages” for themselves — profiles in which they detail their lives, loves, friends and other teen obsessions. Most home pages come complete with pictures, daily blogs and even video clips. Once a new home page is posted, others are able to peruse it and post messages on it largely as they choose.

Gradually each child builds up a bigger and bigger network of online contacts and friends — all well away from the prying eyes of teachers and parents.

Although largely harmless, the boom in social networking sites has been accompanied by the spread of “cyberbullying”, a trend that some experts believe is fast getting out of hand and may be being exaggerated in the UK by Bebo’s focus on schools.

IN a recent survey of 500 teenagers carried out by Microsoft, more than one in 10 said they had been bullied online.

Stephanie Godwin, a 13-year-old from Gloucester, was subjected to a year of bullying on the internet. She was sent a stream of abuse on her website and became so scared she refused to go to school. One of the messages read: “Gay! Ur a f****** fat cow and a fat f***. U wanna shut ur f****** mouth cos you is gonna get banged”.

Debra, her mother, said: “I couldn’t believe what these kids were doing, she just couldn’t escape it.”

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