NHK analyzed more than 1,100 cases of flaming over a 500-day period from June 2016 to October 2017. Shinichi Yamaguchi of the International University of Japan cooperated in the survey.
They looked into the 420 comparatively larger attacks of more than 1,000 Twitter retweets. The targets of these attacks were divided into the following 7 categories: politicians and municipalities, businesses and commercial organizations, press and media, celebrities and academics, YouTubers and bloggers, ordinary people, and others.
They found that ordinary people were the most targeted, with 118 cases, or 27.6 percent. This was followed by 89 cases, or 20.8 percent, targeting politicians and municipalities, 81 cases, or 19 percent, targeting businesses and commercial organizations, and 64 cases, or 15 percent, targeting the press and media.
As for the average number of retweets per category, NHK found that the largest number, at 18,175, were directed at ordinary people, followed by 11,189 retweets directed at businesses and commercial organizations, and 8,232 at the press and media.
Yamaguchi says not only are ordinary people at high risk of being flamed -- attacks toward them are particularly prone to becoming large-scale.
A victim's experience
A woman in her 30s who lives near Tokyo became a victim of flaming 2 years ago when she tweeted about her hobby.
She received a barrage of criticism online such as "Gross" and "Don't boast when you know nothing."
The woman says she couldn't focus on her work. She would keep checking online whenever she went to the toilet. When she fought back on social media, she would attract even more attention, and the flaming would get worse.
Ultimately, her identity was exposed. Her real name and her photos were posted online.
The woman says she felt scared. She would wonder if she was being watched, or if someone might realize who she was and point her out.
Flaming can escalate into online lynching
Ishibashi Kensetsu Kogyo, a construction company in the city of Kitakyushu, began to receive hostile phone calls on October 11th. Officials say there would be silence or jeering on the other end.
President Hidefumi Ishibashi says the company has received more than 100 such calls. He says his workers have no choice but to take calls during business hours.
The calls started after a large truck hit a van on the Tomei Expressway in Kanagawa Prefecture in early October. A couple in the van was killed.
The driver of the truck was arrested on October 10th. His surname happened to be Ishibashi, the same as the president of the construction company. The driver also lived near the company.
That made some people think there was a connection between them, and triggered rumors that the president was the driver's father.
Ishibashi says although he tried to explain that they were unrelated, the callers would call him a liar or tell him to stop playing dumb.
After the driver was arrested, the home address of the president, which he had kept confidential, was released online.
The president temporarily closed his office because he felt he was in danger. He made his children stay at home instead of going to school. Ishibashi says he is scared, and wonders whether he and his family will be attacked.
How targets are identified
A man in his 20s says he has found and revealed the personal data of dozens of people.
He says that in the case of Twitter, third parties cannot access the content of undisclosed accounts.
But if they have friends with public accounts, anyone can see those tweets. If the friend calls the target by his/her real name or sends a birthday message, the target's real name and date of birth can be identified.
He says he likes the thrill he gets from identifying a target, and says it's like combining various bits of information to solve a puzzle.
Responding to flaming
NHK asked a lawyer familiar with Internet issues, Yohei Shimizu, about how to deal with flaming.
Shimizu says people should absolutely avoid making excuses or fighting back against the attacker on social networking sites, because such actions could make things worse.
He points out that flaming often calms down spontaneously after a while, but the safest way to deal with it is to delete the account before personal information can be identified.
Shimizu says that when the victim's personal information has already been identified and exposed, causing trouble in his/her daily life, further action is necessary.
He says many operators of online forums and content-curation sites respond to their users' requests to delete specific information. He points out it's important to handle each issue before the information spreads.
Shimizu adds that people should consider filing a criminal complaint or a civil lawsuit in a malicious case.
He says it's necessary to identify the people engaged in online lynching or defamation when taking legal action.
But he says identifying attackers is difficult for ordinary people and a retention period is set for online information, so victims should consult with a lawyer or police quickly.