Kim Hyo-bi doesn't want her picture taken any more. Not after the 22-year-old student's portrait wound up on a photo-sharing Web site last summer with her face colored and distorted to make her look silly, titled alongside the original as "Before and After."

She tried to simply forget about it, but she couldn't. She was barraged with calls from friends who saw the page, and the humiliation and feeling of being violated caused her several sleepless nights.

"I always thought that it is something [that] only could happen to other people," Kim said.

South Korea is the world's most wired country, boasting the highest per capita rate of broadband Internet connections. But there is a growing sense that high-tech prowess hasn't been matched by the development of a mature online society, creating a growing problem of what is known here as "cyberviolence."

That includes anything from online insults to sexual harassment and cyberstalking, and complaints over such offenses more than doubled last year to 8,406, according to the Korea Internet Safety Commission. The most complaints were for slander, which tripled to 3,933 cases in 2005.

This winter, prosecutors broadened their campaign against online harassment and brought the first case against Internet users for comments they had posted on the public feedback section of a Web site.

The case was brought by Lim Soo-kyoung, a controversial figure who was imprisoned for three years after an illegal visit to North Korea in 1989.

She filed a complaint against 25 people for making allegedly offensive comments on Web sites about a news report on her son's drowning death in the Philippines. Among the thousands of comments were remarks scoffing at the death and using insulting language in reference to Lim's past history with the North.

Prosecutors have called for summary judgment against all 25 defendants, who will be charged with criminal contempt or slander and face a fine of 1 million won ($1,030), said Seok Dong-hyun, a Seoul city prosecutor in charge of the case.

"We felt a strong need to stop this practice as soon as possible," Seok said.

One of the most well-known recent cases of online humiliation involved a woman who failed to clean up after her dog defecated inside a subway car last year. Another passenger took a photo with a mobile phone and posted it, drawing widespread condemnation from Internet users.

Now, law enforcement and the government are taking action.

Trying to prevent anonymous attacks, the government said in December it would require Web sites to confirm users' real names before they can post. Many South Korean Web sites already require users to enter their national identification numbers to get accounts, which are verified through a government system.

The government says a bill on the real-name authentication will be submitted to the National Assembly in the first half of this year.

To Kim Bi-hwan, a political science professor at Sungkyunkwan University, cyberviolence won't be solved by official intervention. He said the maturity of country's Internet society hasn't kept pace with technological innovation.

"Promoting a self-examination of Internet society should come before trying to restrict Internet users by any regulations," he said. "Otherwise the same problems will keep occurring in different forms."

Kwak Keum-joo, a psychology professor at Seoul National University who has studied the issue, said people who post malicious remarks often get hooked on the habit of seeing others respond to their inflammatory remarks.

When they don't get the response they want, "they get angry and also tend to act more aggressively as they are granted anonymity," she said.

Some Web sites are taking matters into their own hands, seeking to actively filter comments. South Korea's Cyworld site, home to a hugely popular blog hosting service with 17 million registered members, has 115 employees who encourage proper Internet etiquette and another 20 monitoring for malicious remarks and slander.

Victims of cyberviolence can suffer from insomnia along with anger and feelings of insecurity, said psychiatrist Kim Jin-se, who has treated patients with the issue. Soothing them isn't easy, Kim said, because the problem causing their troubles, the Internet, has become an indispensable part of daily life.

He suggested those who are targeted try to ignore the abuse or simply stay offline for a while.

Kim, the student whose picture was altered, said she felt she couldn't go to police with her complaints because she feared it might actually have been posted by a friend. She said she never put the photo on the Web and doesn't know how it got there.

She now warns friends not to use her photo on the Web and remains keenly aware of any cameras around her. In South Korea, of course, cameras are essentially everywhere, since most mobile phones have them.

On a recent shopping trip, Kim was startled by the sound of camera shutters and the sight of flashes.

"Unfortunately," she said, "it still irritates me."