How TikTok swept the internet

On the night Shelby Renae first went viral on TikTok, she felt so giddy she could barely sleep. She’d spent the evening painting her nails, refreshing her phone between each finger — 20,000 views; 40,000 — and by the next morning, after her video crossed 3 million views, she decided it had changed her life.

She didn't really understand why it had done so well. The 16-second clip of her playing the video game "Fortnite" was funny, she thought — but not, like, millions-of-views funny. She wasn't a celebrity: She grew up in Idaho; her last job was at a pizza shop. But this was just how the world's most popular app worked. TikTok's algorithm had made her a star.

Shelby Renae, a former pizza-shop worker, posts TikTok videos of herself playing the video game "Fortnite." She has 1.3 million followers and her videos have been liked 37 million times.

Now 25, she spends her days making TikTok videos from her apartment in Los Angeles, negotiating advertising deals and always chasing the next big hit. Many days, she feels drained — by the endless scramble for new content; by the weird mysteries of TikTok's algorithm; by the stalkers, harassers and trolls. Yet still, in her off hours, she does what all her friends do: watches TikTok. "It will suck you in for hours," she said.

If you have not used TikTok, you are rapidly becoming the global exception. In five years, the app, once written off as a silly dance-video fad, has become one of the most prominent, discussed, distrusted, technically sophisticated and geopolitically complicated juggernauts on the internet — a phenomenon that has secured an unrivaled grasp on culture and everyday life and intensified the conflict between the world's biggest superpowers.

Rise of TikTok

The web's most popular app has reshaped American culture, hypnotized the world and sparked a battle between two global superpowers.

Part 1: How TikTok ate the internet.

Part 2: Sorry you went viral.

Part 3: As Washington wavers, Beijing exerts control.

Its dominance, as estimated by the internet firms Cloudflare, Data.ai and Sensor Tower, is hard to overstate. TikTok's website was visited last year more often than Google. No app has grown faster past a billion users, and more than 100 million of them are in the United States, roughly a third of the country. The average American viewer watches TikTok for 80 minutes a day — more than the time spent on Facebook and Instagram, combined.

Two-thirds of American teens use the app, and 1 in 6 say they watch it "almost constantly," a Pew Research Center survey in August found; usage of Facebook among the same group has been cut in half since 2015. A report this summer by the parental-control tool Qustodio found that TikTok was both the most-used social media app for children and the one parents were most likely to block. And while half of TikTok's U.S. audience is younger than 25, the app is winning grown-ups’ attention, too; the industry analyst eMarketer expects its over-65 audience will increase this year by nearly 15 percent. (AARP last year even unveiled a how-to guide.)

More than just a hit, TikTok has blown up the model of what a social network can be. Silicon Valley taught the world a style of online connectivity built on hand-chosen interests and friendships. TikTok doesn't care about those. Instead, it unravels for viewers an endless line of videos selected by its algorithm, then learns a viewer's tastes with every second they watch, pause or scroll. You don't tell TikTok what you want to see. It tells you. And the internet can't get enough.

"We’re not talking about a dance app," said Abbie Richards, a researcher who studies disinformation on TikTok, where she has half a million followers. "We’re talking about a platform that's shaping how a whole generation is learning to perceive the world."

The Washington Post's TikTok account has more than a million followers. One in three TikTok viewers in the United States regularly use it as a source of news.

TikTok's cultural influence on a new generation of media has led to some astounding ripple effects. Viral videos of people delighting in their favorite books, many of them with the hashtag #BookTok, which has 78 billion views, helped make 2021 one of the publishing industry's best sales years ever. Books from the author Colleen Hoover, BookTok's biggest star, have sold more copies this year than the Bible, according to data from NPD BookScan, which tracks sales at 16,000 stores nationwide.

America's biggest technology innovators are reinventing themselves in TikTok's image, not only in developing short-video copycats — Meta's Reels, YouTube's Shorts — but in swapping out networks of friends and families for feeds of strangers chasing viral glory. TikTok's model could soon shape the entire internet.

But TikTok's ownership, by the Beijing-based tech giant ByteDance, has also made it one of the biggest pariahs in Washington. Former president Donald Trump tried to dismantle it. Top branches of the U.S. government and military have banned it from government-issued phones. And members of Congress insist it could be a Trojan horse for a secret Chinese propaganda and surveillance machine.

Even as the app has transformed into a public square for news and conversation, TikTok's opaque systems of promotion and suppression fuel worries that China's aggressive model of internet control could warp what appears there. Many users already are self-censoring, adopting a second language of code words — "unalive," not dead; "procedure," not abortion — in hopes of dodging the app's censors and preserving their chances at online fame.

TikTok executives have argued they aren't influenced by government agendas and want only to foster an entertainment platform that is fun and conflict-free. They have worked to soothe doubts and make friends in a hostile Washington by hiring U.S.-based specialists, promising transparency and piping American users’ data through servers in the United States.

But former TikTok employees and technical experts argue that the company's fixes do nothing to address its biggest risk: that its top decision-makers work in a country skilled at using the web to spread propaganda, surveil the public, gain influence and squash dissent. That crisis of trust has led to an ongoing debate among U.S. regulators: whether to more closely monitor the app or ban it outright.

Many TikTok creators say speculation about the app's Chinese roots distracts from the more grounded issues they face as a result of its explosive growth. TikTok's ability to make anyone go viral overnight, they say, has meant that the anger and pressure once endured mostly by big influencers have become facts of life for the masses.

Drew Maxey, a high school literature teacher in St. Louis, said he has gotten used to seeing glimpses of TikTok in class and hearing its sounds in the school hallways. It has become the main way most students socialize and pass the time; he's even become a TikToker, gaining more than 50,000 followers with videos that use comic books as literary tools.

Drew Maxey, a high school teacher in St. Louis, uses comic books to explain literary concepts to his more than 50,000 TikTok followers. He worries the app's rules could be "training a whole generation of people not to say what they actually mean."

But he worries about how TikTok's enigmatic machinery and students’ desire for viral attention have already shaped how some of them talk and behave. He's started changing his wording, too; on some book videos, he won't even say the word "death," anxious it might stunt his reach.

"Everything they need, they get from TikTok," he said. "Yet we’re training a whole generation of people not to say what they actually mean."

TikTok starts studying its users from the moment they first open the app. It shows them a single, full-screen, infinitely looping video, then gauges how they react: a second of viewing or hesitation indicates interest; a swipe suggests a desire for something else. With every data point, TikTok's algorithm narrows from a shapeless mass of content to a refined, irresistible feed. It is the ultimate video channel, and this is its one program.

The "For You" algorithm, as TikTok calls it, gradually builds profiles of users’ tastes not from what they choose but from how they behave. While Facebook and other social networks rely on their users to define themselves by typing in their interests or following famous people, TikTok watches and learns, tapping into trends and desires their users might not identify.

The system runs on a sophisticated machine-learning engine — ByteDance researchers have championed its "sub-linear computational complexity" — but to TikTokers, the process could not be simpler. Launch the app. See the video. Passively consume.

TikTok fans say they’ve been both surprised and unsettled by an algorithm that can read them eerily well, showing them videos they never searched for or even realized they wanted to see: One creator's parody of an algorithmic flow chart narrowed from "teenage thirst traps" to moms and lumberjacks before reaching "videos only 10 people understand." And few places on the web can match TikTok's constant promise of surprise delight: If a viewer doesn't like what's on, there's always another video, one swipe away.

From the outside, watching someone use TikTok mostly looks like mindless swiping. But this system of serendipitous reward is the app's backbone, and it turns entertainment into an endless game. Every swipe could bring something better, but viewers don't know when they’ll get it, so they keep swiping in anticipation of something they might never find. It's satisfying enough to keep people interested and so unsatisfying they don't want to stop.

TikTok tells advertisers that these "continuous cycles of engagement" make it more memorable, emotional and immersive than TV. A company-funded study that used brain-imaging scans on test subjects found that TikTok users engaged with the app about 10 times a minute, twice as often as its social media peers. "The TikTok audience is fully leaned in," a marketing document said.

The app's infectiousness is so widely accepted that it's become an inside joke. Videos with the #tiktokaddict hashtag have nearly 600 million views. One audio clip — a woman saying, "Like this video if you should be doing something else but instead you’re watching TikTok because you downloaded it as a joke and now you’re addicted" — has been pasted onto more than 70,000 separate videos and "liked" tens of millions of times.

TikTok's infectiousness has become an inside joke. Videos with the #tiktokaddict hashtag have been viewed nearly 600 million times.

The average number of hours each American user spent every day on TikTok exploded 67 percent between 2018 and 2021, while Facebook and YouTube grew less than 10 percent, investment analysts at Bernstein Research wrote in an August report. TikTok has replaced "the friction of deciding what to watch," the researchers said, with a "sensory rush of bite-sized videos … delivering endorphin hit after hit."

For viewers who’ve been scrolling too long, TikTok shows "take a break" alerts urging them to "get some water and then come back later"; scrolling past them has become a meme in itself. In June, the app started sending routine reminders to viewers showing how long they’d been watching; teenage viewers are now nudged to limit their TikTok time if they scroll more than 100 minutes in a day.

TikTok's mesmerizing appeal has made it effectively mandatory for modern stars like the Puerto Rican rapper Bad Bunny, who in January got more than 90 million views on one of his first videos, in which he expressionlessly eats Froot Loops. Industries that once wrote the playbook for appealing to mass audiences are now desperate for TikTok's viral boost: A new box office record for the July 4 weekend was set thanks largely to an absurd bit of TikTok meta-comedy — packs of suited-up "Gentleminions" mobbing the premiere of "Minions: The Rise of Gru."

The Puerto Rican rapper Bad Bunny has used his TikTok account to share new songs, dance routines and slices of life. One video, in which he eats Froot Loops, has been viewed more than 90 million times.

But many of the app's best-known names have become celebrities purely on the basis of TikTok itself. Khaby Lame, a 22-year-old former factory worker from Italy, has 150 million followers, 60 million more than Trump had on Twitter at his peak. Videos by Charli D’Amelio, an 18-year-old dancer from Connecticut, have been liked 11 billion times.

The app flourished by making the creation of eye-catching videos accessible to anyone, with giant libraries of free music clips, editing tools, camera effects and augmented-reality filters in a simple, immersive interface. TikTok's central "For You" feed serves up videos without context or dates, making everything feel relevant and new.

And unlike YouTube and Instagram, where creators are forced to compete with established influencers’ polished productions, even the simplest, silliest or most spontaneous TikToks can become massive hits. Quick "duets," "stitches" and "remixes," where people riff off or react to someone else, are widely shared and given almost instant affirmation. Many use the app's "green screen" feature — in which their heads float over a tweet or chart or video — to offer criticism or commentary in the style of a TV news report.

TikTok creators, including Natasha Cougoule and Eli Rallo have used app video features such as "green screen" to present a new style of online commentary.

For young viewers who see social media influencer as a popular career path, the allure is obvious. Teachers talk about students skipping class to record dances in the bathroom; Buddhist shrines in Nepal feature "No TikTok" signs. John Christopher Dombrowski, a Cornell University student whose TikToks about science facts have earned him 2.8 million followers, told the Information he's paid his college tuition with ad-deal money from Adidas and Lancôme. "Social media is the new American Dream," he said.

TikTokers are increasingly using the app as a visual search tool; 40 percent of Generation Z respondents to a Google survey this year said they had opened TikTok or Instagram, not Google, when searching for nearby lunch spots. (One tweet in June, "I don't Google anymore I TikTok," has been ‘liked’ 120,000 times.)

And as Americans’ trust in news organizations has fallen, TikTok's role as a news source has climbed. One in three TikTok viewers in the United States said they regularly use it to learn about current events, Pew Research Center said last month. In the United Kingdom, it's the fastest-growing news source for adults. (The Washington Post's TikTok account has more than a million followers.)

TikTok has been credited with helping supercharge book sales. Books from the author Colleen Hoover — popular with TikTok creators including Kendra Keeter-Gray and Sydney Blanchard — have sold more in the United States this year than the Bible.

Thanks to its gravitational pull on creators and audiences, the app's videos now encompass practically every topic on earth. There is fishing (#fishtok, 14 billion views), farming (#farmtok, 7 billion) and role-playing (#medievaltiktok, 4 billion). There are TikTok cops, lumberjacks, nurses and nuns. There is domestic bliss (#cleantok) and chaos (#cluttercore). There is #happiness (16 billion views) and #pain (76 billion).

And, this being the internet, there are TikTok animals. The Chipmunks of TikTok account, with 15 million followers, features Bubba, Dinky, SpongeBob, Stinky and other chipmunks gobbling up hazelnuts; one video, "Fill the cheeks Squishy," has been viewed more than 280 million times. Brad Zimerman, a 53-year-old karate instructor in St. Louis, said he started the account while out of work during the pandemic and now makes money through creator payouts from TikTok and YouTube, as well as from personalized happy-birthday videos on Instagram.

The "Chipmunks of TikTok" account — featuring the mealtimes of Squishy, top, SpongeBob and Mooshy — has 15 million followers. "No one even knows who I am," creator Brad Zimerman said.

Zimerman said he doesn't do brand sponsorships and declined to share how much he makes, saying only that he's earned more money from chipmunk videos than his actual job. One influencer-marketing group estimated that, with his account's level of interest, he could charge up to $14,000 per post.

"I get thousands of offers to do deals with my chipmunks," he said. "No one even knows who I am."

After cornering the market on entertainment, TikTok began offering its model of behavioral tracking and algorithmic suggestion to advertisers, promising them a way to know which ads people find most compelling without having to ask. It was an instant hit: The company's ad revenue tripled this year, to $12 billion, according to eMarketer estimates, and is expected to eclipse YouTube at nearly $25 billion by 2025. In the United States, the cost to advertisers for TikTok's premium real estate — the first commercial break a viewer sees in their feed, known as a "TopView" — has jumped to $3 million a day.

Beyond traditional marketing, TikTok has rapidly industrialized the way companies pay young people to hawk their stuff. TikTok runs a giant catalogue of people, the Creator Marketplace, that companies can use to sort creators by their interests and follower counts; the service is invite-only, and creators have to post frequently if they want the chance to get paid. Influencers paid to promote goods in their videos now make more ad money on TikTok than Facebook: roughly $750 million, U.S. estimates from Insider Intelligence show. (Instagram, which beats both of them, this summer debuted its own "Creator Marketplace" clone.)

TikTok also takes a cut of the virtual tips, or "Video Gifts," that fans pay to creators with its central currency of TikTok "coins." Displayed online as neon roses and doughnuts, this economy now rivals that of a small nation: In the past three months, TikTokers spent more than $900 million inside the app — the highest quarterly spending for any app in history.

TikTok's diverse creator base has made the app into a showcase for radical self expression. It's also inspired jealousy inside Facebook, where bored users are leaving en masse.

At a time when Silicon Valley's stock prices are crumbling, TikTok's success has triggered deep jealousy — especially for Facebook, which in February reported it had lost users for the first time in its 18-year history. (The top link on all of Facebook in the second quarter of this year was TikTok, Facebook's parent company Meta said.)

Meta tried beating TikTok by hiring a Republican lobbying firm to undertake a secretive letter-writing and lobbying campaign calling it the "real threat" to America's teens. But by the summer, Meta ended up just copying TikTok's style, ditching its focus on people's friends and families and swapping in computer-selected unknowns.

Not everyone was happy about it. On internal message boards, employees have griped that Facebook is abandoning its strengths, such as "the social graph and human choice." The celebrity socialite Kylie Jenner told her 360 million Instagram followers the company should "stop trying to be" TikTok. But there are some early signs that these copycats are succeeding. YouTube said in June that its Shorts service was being watched by 1.5 billion users every month — beating the 1 billion user count TikTok reported last fall.

TikTok, however, seems bent on taking on a wider range of digital life. It's tested features for interactive minigames and job résumés. It started selling concert tickets. It built a live-streaming business used for meal-cooking showcases, lottery scratch-offs, tarot readings and apartment tours. And it tested a shopping feature that would let viewers buy products from QVC-style live streams in a few quick taps.

Even without that expansion, there can be no denying that TikTok has become a world-shaping force of its own — so colorful and compelling that many viewers find it hard to quit. That's even the case in Russia, where the company, abiding by Kremlin directives, has blocked everyday Russians from posting new TikToks or seeing any videos from outside the country since the Russian military invaded Ukraine.

The TikTok people watch in Russia has become its own parallel universe, frozen in time — an endless stream of old Russian videos and pro-Kremlin propaganda. But many young Russians continue to use it "quite actively" nearly eight months into the war, said a few who spoke with The Post on the condition of anonymity because of the country's draconian speech laws.

Some teens said they use technical workarounds to see foreign TikToks, risking punishment for a glimpse of the outside world. But one 18-year-old said he just settles for watching whatever the algorithm shows. "Yes, all videos are old," he said. "But it's still enough."

Will Oremus, Natalia Abbakumova and Taylor Lorenz contributed to this report.

Editing by Mark Seibel, Jayne Orenstein and Karly Domb Sadof. Additional editing by Dave Jorgenson, Virginia Singarayar, Shannon Croom, Drea Cornejo and Monique Woo. Design and development by Emily Wright.