It was nearly 4 a.m. in China when I hit play on the video entitled “Zhao Benshan: King of Poetry!”, but the ghosts of a thousand past viewers were still distracting me with their chatter.

The video is a remix collage of CCTV Spring Festival Gala skits starring iconic comedian Zhao Benshan—source material familiar to anyone who grew up near a TV in China—edited and AutoTune’d into a military-grade earworm. But I could barely piece that together through the fog of text left behind by previous viewers: laments about the catchiness of the song, compliments to creators, jokes, and echoes of favorite lyrics. In the end, I had to watch the video twice, as I often do on the social video site Bilibili: once with the bullet comments turned off so that I could follow the source material, and once more for the real experience, the chitchat obscuring the content.

Bullet comments, or 弹幕 (“danmu”), are text-based user reactions superimposed onto online videos: a visual commentary track to which anyone can contribute. When a beloved character dies in a web series, a river of grieving kaomoji (╥﹏╥)—a kind of emoticon first popularized in Japan—washes over whatever happens next. A child’s overly honest response to a TV anchor’s question triggers a blizzard of different ways to signify laughter (2333, 哈哈哈哈). When the (Chinese) good guy punches out the (American) bad guy in 2017’s blockbuster Wolf Warrior 2, jingoistic cries of “Long live China!” erupt across the screen. Each comment is synchronized to an exact moment in the video, and will fly across the screen on cue on every subsequent replay. On particularly popular videos, they pile up so thick that they can cover the original entirely. The result is a viscerally social experience, like an opening night crowd at a movie theater that you can summon anytime.

In the West, the Chinese internet is mostly depicted in negative terms: what websites and social platforms are blocked, what keywords are banned, what conversations and viral posts are scrubbed clean from the web overnight. This austere view is not inaccurate, but it leaves out what exactly the nearly 750 million internet users in China do get up to.

Take a look at bullet comments, and you’ll have a decent answer to that question. They represent the essence of Chinese internet culture: fast-paced and impish, playfully collaborative, thick with rapidly evolving inside jokes and memes. They are a social feature beloved by a generation known for being antisocial. And most importantly, they allow for a type of spontaneous, cumulative, and public conversation between strangers that is increasingly rare on the Chinese internet.

Stray Bullets

Like much of what’s popular on the Chinese internet, bullet comments are an invasive species from Japan. When China’s borders loosened to enable freer trade and travel in the 1980s, Japan's well-established media industries were the best positioned, both geographically and culturally, to take advantage of the wide-eyed new market. Alongside Nikon cameras and Yamaha keyboards, Japanese “ACG”—animation, comics, and games—rushed into China. For Chinese kids growing up during the 1990s, manga and anime series like Doraemon, Sailor Moon, Slam Dunk, and One Piece became important cultural touchstones.

The most fervent fans began creating infrastructure to feed their hobby. Resellers smuggled or imported books, videos, and merchandise from Japan, sometimes via Taiwan and Hong Kong. Volunteer groups developed efficient pipelines for distributing and subtitling the latest episodes of anime shows first on VHS tapes, then online. Organizers created offline and online events and conventions for fans to gather. All of this activity opened the door to even more widespread interest in ACG in later generations. A recent industry report estimates that there are 300 million self-identified ACG fans in China, and that 97 percent of them were “post-’90s” and “post-’00s”—the generations defined by being born after 1990 and 2000, respectively.

When a Japanese site called Niconico invented the idea of writing comments directly on top of YouTube videos in 2006, it took less than a year for a clone of the platform to appear in China. In Japanese, the system was named 弹幕 (danmaku), or “bullet curtain,” after a subgenre of hardcore shoot-em-up games in which enemies fly in formation across the screen, like the famous arcade game Galaga on steroids. Both kinds of danmaku—the games and the comments—required their audience to process an overwhelming amount of visual stimulation at high speeds.

In China, several sites seeking to clone the Niconico experience copied the feature, as well as the Japanese characters for the name, which are pronounced “danmu” in Chinese. Today, the most successful of these clones by far is Bilibili, a social video site that has become an entertainment staple for young people in China.

Like many of the other video platforms in China, Bilibili combines officially licensed shows and movies (both domestic and international) with user-uploaded videos and livestreams. ACG content still dominates the site, but Bilibili’s hordes of bullet commenters can now react to just about everything else too: makeup tutorials, documentaries, music videos, vintage commercials, and “Kichiku,” a Niconico-originated genre of manic Auto-Tune’d parody remixes such as the one of Zhao Benshan mentioned above.

Bilibili isn’t China’s biggest video platform by a long shot, but it does maintain an unusually tight grip on youth culture: over 90 percent of Bilibili’s 93 million monthly active users are under the age of twenty-five. Bilibili’s finger on this pulse has translated into major financial success: the company has, at time of writing, a market capitalization of $5.41 billion on the New York Stock Exchange. It’s also the primary sponsor of one of China’s most popular basketball teams, which Yao Ming was playing for when he was discovered by the NBA and which he now owns: the Shanghai Bilibili Sharks. Even the central government has embraced the platform in a bid to reach young people: in January 2019, Bilibili was one of two video sites chosen to distribute a government-commissioned, domestically produced anime series about the life of Karl Marx. During the opening sequence of the first episode, the bullet comments are a blizzard of check-ins from high schools and colleges around the country.

As the rest of the Chinese media industry tries to replicate Bilibili's success with the coveted post-’90s demographic, bullet comments have spread from platform to platform as if by airborne spores. Nearly every major video site in China—Youku, Tencent Video, iQiYi—now has a bullet comment feature, as do most of the biggest live-streaming platforms. In fact, many of them actually have Bilibili’s exact bullet comment feature, which was open-sourced by the company in 2015. The invasive social feature can also be found in more unlikely places: apps for reading comics or streaming music, e-commerce platforms, even narrative cutscenes in the middle of popular mobile games. Bullet comments have become a ubiquitous social layer woven into any digital experience.

The Primordial Soup of Memes

Li Moqiang, cofounder of the Chinese electronics company Xiaomi, describes his first encounter with bullet comments in his 2014 book 参与感 ("Togetherness"). Fifteen minutes in, his eyes were watering. He felt overwhelmed, and had trouble focusing on anything. But after enduring it for another thirty minutes, he found that he had developed the ability to switch his attention between the comments and the underlying video at will—a sort of Magic Eye trick for processing content and commentary at the same time.

Tech leaders like Li are willing to risk eye strain to pay attention to bullet comments because the fast-paced conversations and roasting sessions they enable beget many of the memes and trends that eventually infect Weibo, WeChat, and the rest of the Chinese internet. Individual bullet comments rarely go over a dozen characters, so commenters rely on a rich repertoire of text-based memes—from internet shorthand to clever wordplay on ancient Chinese sayings—to express themselves efficiently. Even for people fluent in Chinese, deciphering a video’s worth of bullet comments can be a crash course in internet tropes, rudimentary Japanese, Chinese history, regional stereotypes, and continuously updated pop culture references.

On top of trading witticisms, bullet commenters also play informal, emergent games with each other and with the content. Commenters will synchronize their comments to create a wall of text that shields future viewers from gruesome or scary shots, or create 五毛特效 (“fifty-cent special effects”) like populating a night sky full of ASCII stars. Other commenters spontaneously collaborate to generate subtitles in various languages—both earnest and facetious—as "the Eight-Nation Alliance Caption Club,” a wry reference to the international military coalition that invaded China following the Boxer Rebellion. If a character in a show holds up a sudoku puzzle for even a second, a bullet commenter will probably try to solve it.

To maintain a healthy comment culture on a platform where any toxicity would be literally foregrounded, Bilibili has taken an approach to community management that feels downright heretical in the growth-obsessed tech industry. While any visitor to the site can watch its videos, only fully registered members are allowed to upload videos or leave a bullet comment. Currently, registration involves passing a hundred-question test about anime trivia (“In the Fate series, which magic is the Einzborn family fighting over the Holy Grail in hopes of recovering?”) and bullet comment etiquette (“Which of the below comments is not trolling? A. Should I use cilantro or not? B. I don’t want to be a person anymore C. Which kind of tofu is most delicious? D. This show isn’t as good as XX” [The answer is B.]).

Incredibly, this is actually the simplified version: the test was once even longer and more difficult to pass, earning it the nickname the “Chinese otaku high school examination” in reference to the infamous, grueling, week-long test that single-handedly determines college admissions around the country. Despite this significant hurdle, 31 million users have completed the Bilibili registration process, many with the help of cheat sheets circulated around the internet. This self-enforced gatekeeping process has given the site an unique advantage on a playing field where any feature can be cloned: a community and a bullet comment culture widely regarded as the best around.

Heat and Noise

热闹 (rè nào) is hard to concisely translate into English with its personality intact. Literally meaning "heat and noise," it describes an atmosphere of bustling conviviality: a balance point between hygge and lit. A night market sizzling with smells and chatter is re nao, as is a table-slapping game of mahjong after a big family meal. Re nao is as central to the Chinese vision of the good life as freedom is to America’s; it’s deep-rooted in a way that defies rationality.

For young Chinese people, bullet comments are a dose of re nao that fits better into their lives than the karaoke, mahjong, and alcohol-fueled banquets preferred by their elders. The post-’90s generation is stereotyped—and often self-identifies—as shut-ins. A Peking University study of 3000 post-’90s people from across China found that 62 percent ranked “staying at home to surf the web” as their favorite activity. “Hanging out with friends” came in at 39 percent, while “going to the bar” was ranked lowest, at only 3.4 percent.

This shift away from traditional conviviality is a consequence of societal changes that uniquely impact the younger generation. As people move away from their hometowns and alma maters, traditional social bonds fray. They are then further strained by the urban sprawl that makes it challenging to keep up with friends in the same city. Many members of the post-’90s generation are also exhausted from the “996” work culture that has taken root in Chinese startups and other young companies: 9 am to 9 pm, 6 days a week, with no overtime pay. It’s easy to see the appeal of anonymous togetherness on Bilibili, a shortcut to re nao that requires no jostling commute, no reservation at a crowded restaurant, no friends in the same city or neighborhood.

The hyper-re nao enabled by internet features like bullet comments might be one of the more potent drugs ever created. In the US, we are just starting to understand the potential dangers of this high—how the addictive thrill of online togetherness can leave lonely people vulnerable to radicalization, how the echoing of one’s opinions by a crowd will always be more compelling than any fact. But the Chinese government has long been attuned to the thin line between a carnival and a riot; after all, the Cultural Revolution, a display of youthful re nao gone very wrong if there ever was one, is in living memory for everyone in charge.

In recent years, that insight has led the government to encourage more siloed digital nooks, such as WeChat’s 500-person-max group chats, and to more heavily police the open digital spaces where enough strangers can congregate to become a problem. The type of digital spaces, in other words, that bullet comments enable.

The government’s embrace of Bilibili, then, may just be a way of keeping it on a tight leash. In 2017, Bilibili’s app was temporarily pulled from mobile stores as part of a larger crackdown on “unproductive culture,” which also saw hip-hop artists with tattoos banned from television. This warning shot was fired despite the politically apathetic, if not downright patriotic tone of most comments on the site: Bilibili users are much more likely to bicker over whether Marvel or DC is the superior provider of superhero movies than to poke fun at Party leadership. But it is the very strength of its capacity for re nao that makes bullet comments a politically risky format: a crowd, no matter how anime-obsessed, just needs the right spark to become a mob.