Cyberbullies: cell phones, instant messaging, and the internet are giving bullies new ways to harass their classmates, even they're not at school.

The fight started at school, when some girls in the eighth grade stole a pencil case filled with makeup that belonged to a new classmate, Amanda Marcuson, and she reported them. But it did not end there.

As soon as Amanda got home, the instant messages started popping up on her computer screen, calling her a tattletale and a liar. Shaken, she typed back, "You stole my stuff!" They responded with a series of ugly epithets.

That evening, when Amanda was at a basketball game, the barrage of electronic insults did not stop. Like a lot of other teenagers, Amanda has her Internet messages automatically forwarded to her cell phone, and by the end of the game she had received 50--the limit of its capacity.

"It seems like people can say a lot worse things to someone online than when they're actually talking to them," says Amanda, 14, of Birmingham, Mich.

Bullying has been around as long as schoolyards. But with cell phones, instant messaging, and the Internet, bullies are finding new ways to harass their classmates away from school.

No longer confined to school grounds or daytime hours, these "cyberbullies" are using technology to inflict pain from afar. And some say the distance between bully and victim on the Internet is leading to an unprecedented--and often unintentional--degree of brutality.

"We're always talking about protecting kids on the Internet from adults and bad people," says Parry Aftab, executive director of WiredSafety.org, a nonprofit group that has been fielding a growing number of calls from parents and school administrators worried about bullying. "We forget that we sometimes need to protect kids from kids."

OVERLOOKED BY ADULTS

For many teenagers, online harassment has become a part of everyday life. But schools, which tend to focus on problems that arise on their property, and parents, who tend to assume that their children know better than they do when it comes to computers, have long overlooked it. Only recently has it become pervasive enough that even the adults have started paying attention.

The new weapons in the teenage arsenal of social cruelty include stealing each others' screen names and sending inflammatory messages to friends or crushes, forwarding private and often sexually explicit material to people for whom it was never intended, and anonymously posting derogatory comments about fellow students on blogs.

"I have kids coming into school upset daily because of what happened on the Internet the night before," says Susan Yuratovac, a school psychologist in Beachwood, Ohio. "'We were online last night and somebody said I was fat,' or 'They asked me why I wear the same pair of jeans every day,' or 'They say I have Wal-Mart clothes.'"

TRIPPED UP BY THE INTERNET

Tools like e-mail messages and blogs enable the harassment to be both less obvious to adults and more publicly humiliating, as gossip, put-downs, and embarrassing pictures can circulate among a wide audience with just a few clicks.

To a large degree, psychologists say, teenagers are being tripped up by the same property of the Internet that has compelled many adults to fire off an e-mail message they later regret: the ability to press "send" and watch it disappear makes it seem less real.

But a growing number of teenagers are learning the hard way that words sent into cyberspace, as ephemeral as they seem, can have more severe consequences than a telephone conversation or a whispered confidence.

For instance, a sophomore at Fieldston High School in New York agreed not to return this fall after a racist comment she wrote in an instant message to a friend about a boy who had spurned her ignited controversy last spring. The friend forwarded the message to the boy, and copies were distributed around the school the next day.

Many schools, ill-equipped to handle these new situations, are holding assemblies to talk about them, and experts in traditional bullying are scrambling to prevent them.

"It's so nebulous," says Mary Worthington of the Network of Victim Assistance, a counseling organization in Bucks County, Pa. "It's not happening in the lunchroom, it's not happening on the school bus, yet it can spread so quickly."

Amy Harmon covers technology for The New York Times.