The problem began when Alyssa was in sixth grade. She used an instant messaging program to talk online with all of her friends. But then one day, the messages she received were most unwelcome.
"There's a boy at school, a classic bully. He treats everybody badly," she said. "One day he came online -- somehow he got my screen name -- and started bullying me online, calling me names, telling me I'm stupid and I'm a loser and nobody likes me."
She quickly clicked out of the program, but the next day -- and for the next two weeks -- the harassment continued, even though she'd tell him to "shut up and go away."
"It really got to me," Alyssa said. "He just kept saying such hurtful things. And when you're reading them on the screen, it's so much more impactful than someone saying it. The words sink in."
In cyberspace, kids can use more than instant messaging to torment each other or post personal information. Nasty e-mails, Web sites, cell phone text messages and photos all can be vehicles for everything from mild teasing to serious harassment.
It can "range from somebody calling somebody else names to death threats," said Parry Aftab, executive director of Internet safety group WiredSafety.org, which reports and helps protect people from online dangers.
Such "cyberbullying," Aftab said, is "cyber-harassment when you've got a kid on both sides."
While there aren't hard figures to define the scope of the problem, those who work with adolescents can attest to its pervasiveness anecdotally.
"It's a very serious problem at every school," said Lawrence Shapiro, a child psychologist who has created a board game about bullying called "Don't Pick on Me."
While Alyssa knew who was behind the nasty messages she received, other bullies can make up screen names to hide their identities.
"I think it's just so easy," Shapiro said. "Kids who may never bully in real life, because it's anonymous, they find it much easier."
Kids picking on other kids is hardly anything new. But technology allows it to invade private time and comfortable places.
"The boundaries used to be clear between home and school," Shapiro said. "Home used to be a safe place. Kids could often feel very good about themselves within the family even if they didn't at school."
Aftab said there are four main categories of cyberbullies, each with a different motivation. They include:
The Vengeful Angel: This is a cyberbully who thinks he is righting a wrong or trying to take justice into his own hands. These people think someone's been hurt or abused and they come in and settle things. "They don't realize they are also a cyberbully," Aftab said.
This type of bully is motivated by vengeance. "The easiest way to stop is to look at the situation they're trying to fix and give them other avenues for justice," she said.
The Power Hungry: "They do it to intimidate, they do it for attention, they do it for control," Aftab said. "They do it to show everybody how big and tough they are and they can push others around."
A subset of this group is the offline victim of a schoolyard bully who "may not be strong enough to fight back physically, but they have enough tech skills and the technology to fight back online," Aftab said.
Often they are girls or kids with computer skills. Because they are motivated by ego, Aftab said, the best thing to do is ignore them, but search online to make sure they haven't put false information out on the Web.