Japan's biggest Internet forum, where anonymous netizens trade anything from cooking tips to death threats, has long been an anarchic zone of uninhibited free speech and a magnet for controversy.
This week the raw commentary on 2channel - which with 10 million visits a month is one of the world's largest online bulletin boards - saw tempers flare anew.
A massive hacker attack from South Korea crippled the site in retaliation for users' online slights against Olympic skater Kim Yu-Na, after she beat Japanese rival Mao Asada to take gold at the Vancouver Winter Games.
The site was attacked on Monday, the anniversary of a 1919 uprising in Korea against Japanese colonial rule, and shut down for two days.
Japanese web users counter-attacked by bombarding South Korean sites, including that of the presidential office, according to South Korea's JoongAng Daily, which called the tit-for-tat flaming "infantile".
The Japanese site, www.2ch.net, does not ask for personal ID details and hosts unfiltered views, in contrast to most chat forums where registration and vetting have become the norm in a bid to keep discussion orderly.
"This is a vast group of bulletin boards on everything from hacking to porn," the site tells users. It boasts about 1,000 topics, from politics to sport to manga comics.
"Sender information cannot be detected, so you can access it from your office, school or prison," users are told. "Please write as you like."
The site was launched in 1999 by a college student, Hiroyuki Nishimura, who has since written several books and is a regular on television shows.
Not counting online role-playing games, it is easily Japan's biggest bulletin board by number of users and page views, according to research firm NetRatings Japan.
The site has given space for discussion on touchy subjects, including Japan's royal family, and gay and lesbian life.
Companies and pollsters review the site to build marketing strategies and study the raw pulse of users and consumers.
At their best, the site's postings have spawned books and movies, including a passionate chronicle by a shy man known as the Train Guy who dated a woman and sought advice from fellow 2channel users.
But no-holds-barred messages also voice sexist, nationalistic and xenophobic sentiments, many targeting Chinese and Koreans.
South Koreans were furious recently when a writer said the mob killing of a Korean college student in February in Irkutsk was "Russia's good deed".
At times, users have threatened crimes on the site.
One of them was Tomohiro Kato, who sent messages from his cellphone shortly before he killed seven people in a stabbing frenzy in Tokyo's neon-lit electronics district in 2008, Japan's bloodiest crime in years.
Nishimura, who gave up control of the site last year but maintains interests in many Internet companies, is unabashed about the darker side of 2channel.
"Ten million people come to the site every month. There is no city in the world with a population of 10 million that has no crime," he said.
Tsutomu Kanayama, professor of journalism and communications at Ritsumeikan University in Kyoto, said 2channel laid bare the pluses and minuses of the social media revolution.
"Mainly because of the anonymity system, it has gone too far and is now full of offensive and meaningless comments," he said.
"But on the other hand, it's a positive trial for a future cyber-forum where anyone can pose real opinions freely. It has both a light and a dark side."Reuse content