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So, when did TikTok become popular? TikTok began gaining real traction in 2018, crossed into mainstream popularity during 2019, and became a full cultural phenomenon in 2020 when Covid-19 lockdowns sent its user numbers into the hundreds of millions.
By September 2021, it had reached 1 billion monthly active users faster than any social media platform before it.
What Existed Before TikTok Became Popular — The Origins (2014–2016)
TikTok didn't appear from nowhere. Two earlier apps laid the groundwork for everything that followed.
Musical.ly — The Early Blueprint
In 2014, an app called Musical.ly launched in Shanghai. It let users record short videos of themselves lip-syncing or performing comedy sketches set to popular songs.
The format was simple. It caught on quickly, especially with younger audiences in the US and Europe.
What Musical.ly proved was that short, music-driven video content had genuine appeal and that teenagers, in particular, were willing to spend significant time both creating and watching it.
Douyin — The Chinese Proof of Concept
In 2016, Chinese tech company ByteDance launched Douyin a short-form video app aimed at the Chinese market. Within its first year, Douyin had accumulated 100 million users.
That kind of growth, that fast, told ByteDance something important: the format worked, and it scaled.
Douyin and TikTok are technically the same app running on separate systems Douyin for China, TikTok for everywhere else.
Understanding that distinction matters, because TikTok's global rollout was never a blind experiment. It was backed by a concept already proven at scale.
When Did TikTok Become Popular? It Started With the Global Stage (2017–2018)
Armed with a proven format and a ready-made user base, ByteDance moved quickly to turn a regional success into a global one.
ByteDance Acquires Musical.ly and Launches TikTok Internationally
In September 2017, ByteDance launched TikTok internationally. Shortly after, in November 2017, it acquired Musical.ly paying somewhere between $800 million and $1 billion depending on the source.
The acquisition gave ByteDance immediate access to Musical.ly's roughly 60 million existing users worldwide, most of them already comfortable with the short-form video format.
By August 2018, Musical.ly was formally merged into TikTok. Users were migrated over, accounts were transitioned, and TikTok inherited an established audience it could build on.
2018 — The First Major Milestone
That same year, 2018, as reported by TechCrunch, TikTok surpassed Facebook, Instagram, Snapchat, and YouTube in total downloads for the first time. That's a striking stat but it needs some context.
Downloads vs. Active Users — Why the Distinction Matters
Downloads and active users are not the same thing. A download means someone installed the app. An active user means someone is actually opening and using it regularly.
In 2018, TikTok was winning on downloads, but many of those installs were driven by curiosity. Sustained daily engagement the metric that actually defines popularity came later.
This is a distinction most coverage glosses over. In practice, social media analysts treat monthly active users as the more meaningful indicator of genuine platform health, and by that measure, TikTok's real popularity still had some way to go in 2018.
The First Signs of Real Popularity (2019)
2019 is an underappreciated chapter in TikTok's story. It doesn't get the same attention as 2020, but the groundwork laid that year made the 2020 surge possible.
1 Billion Total Downloads and a Top-Four Global Ranking
By February 2019, TikTok had crossed 1 billion total downloads worldwide. It also became the fourth most-downloaded non-gaming app globally that year.
US teenagers were adopting it in growing numbers, and the content categories on the platform were diversifying beyond dance and lip-sync into cooking, comedy, commentary, and DIY.
The For You Page Starts Doing Its Job
What's often overlooked in discussions about TikTok's 2019 growth is the role the algorithm was already playing. TikTok's For You Page the main feed most users see when they open the app was already serving content based on watch behaviour rather than who a user followed.
Someone with zero followers could post a video and have it seen by millions if the algorithm identified strong engagement signals.
That model was quietly compounding through 2019. Content creators noticed. More creators joined. More content was produced. The cycle fed itself.
The Tipping Point Covid-19 and the 2020 Surge
If there is one year that answers the question of when did TikTok become popular for most people, it is 2020.
How Lockdowns Created the Perfect Conditions
When Covid-19 lockdowns began in early 2020, hundreds of millions of people found themselves at home with little to do and unlimited time on their hands. TikTok already growing, already improving was perfectly positioned to absorb that attention.
In the US alone, TikTok gained over 100 million monthly active users during 2020. Between July 2020 and July 2022, the platform recorded a 45% increase in monthly active users globally.
Viral Trends That Pulled People In
Dance challenges, cooking hacks, humour skits, home workout routines content that was participatory and easy to replicate spread rapidly. The pandemic gave people both the time and the motivation to create, not just consume.
What also changed in 2020 is who was using it. TikTok stopped being primarily a platform for teenagers.
Older millennials, parents, teachers, healthcare workers people who might never have downloaded a short-video app under normal circumstances joined during lockdowns and stayed.
That demographic expansion is what turned TikTok from a popular teen app into a mainstream cultural platform.
TikTok's Growth by the Numbers — Full Timeline
|
Year |
Key Milestone |
|
2014 |
Musical.ly launches in Shanghai |
|
2016 |
ByteDance launches Douyin in China; reaches 100M users within year one |
|
Sept 2017 |
TikTok launches internationally |
|
Nov 2017 |
ByteDance acquires Musical.ly for ~$800M–$1B |
|
Aug 2018 |
Musical.ly merges into TikTok; TikTok surpasses Facebook, Instagram, Snapchat, and YouTube in downloads |
|
Feb 2019 |
1 billion total downloads worldwide; 4th most-downloaded non-gaming app globally |
|
2020 |
Covid-19 lockdowns drive 100M+ US monthly active users; demographic base expands significantly |
|
Sept 2021 |
Reaches 1 billion monthly active users — fastest growth in social media history |
|
2022 |
~1.5 billion users; reported revenue of $9.4 billion |
|
Sept 2023 |
TikTok Shop launches in the US |
|
Jan 2025 |
App goes dark in the US for 14 hours amid ban legislation |
|
Feb 2025 |
~170 million US users; operations continue under extended regulatory deadline |
Why TikTok Grew So Fast — The Factors Behind the Popularity
Growth at this speed doesn't happen by accident. Several specific features and decisions drove TikTok's rise.
The For You Page — A Different Kind of Algorithm
TikTok's algorithm optimises for watch time how long a user actually watches a video, whether they replay it, whether they engage or scroll away.
This is meaningfully different from how Facebook and Instagram historically worked, where the number of followers or likes a creator had heavily influenced visibility.
How TikTok's Approach Differed from Competitors
On Facebook or Instagram, building an audience typically required consistency over months or years. On TikTok, a single video from an account with no followers could reach millions if users watched it through to the end.
That possibility that anyone could go viral drew creators to the platform in large numbers, which in turn generated more content, which kept existing users engaged longer.
Why Follower Count Became Less Relevant
In practice, TikTok's model democratised content discovery in a way other platforms hadn't. Smaller creators found they could build audiences faster on TikTok than anywhere else.
That perception attracted a wave of new content creators between 2019 and 2021, directly fuelling the platform's growth.
Creative Tools That Lowered the Barrier
TikTok offered filters, effects, and an extensive licensed music library from early on. Users didn't need editing software or production skills.
They could produce something watchable in minutes directly from the app. That accessibility mattered particularly for younger users who had ideas but not equipment.
Short-Form Format and Mobile Behaviour
At first glance, short videos seem limiting. In practice, they turned out to match exactly how people were already using their phones in short, fragmented bursts throughout the day. The format wasn't a compromise. It was an advantage.
Who Was Using TikTok — The Audience That Drove Popularity
TikTok's rise wasn't just about the app it was about who showed up first, and who followed them in.
Gen Z as the Primary Growth Engine
Gen Z — broadly defined as people born between the late 1990s and early 2010s was TikTok's earliest and most consistent adopter.
Around 41% of TikTok's users are aged 16 to 24. In the US, 67% of users between the ages of 13 and 18 reported using the app daily, and roughly 16% said they used it almost constantly.
How the Audience Expanded Beyond Teenagers
By 2022, nearly half of all US adults aged 18 to 30 were using TikTok. The platform had moved well beyond its Gen Z origins.
Interestingly, this expansion happened largely without TikTok changing its core product older users simply followed the content into the app.
TikTok's Popularity Compared to Other Platforms
TikTok didn't just grow it grew fast enough to unsettle platforms that had dominated social media for over a decade.
TikTok vs. Instagram and YouTube — Engagement and Time Spent
By 2022, TikTok had surpassed Instagram and Twitter in total downloads. By the end of that year, it was on track to overtake YouTube as the platform where users spent the most time watching content.
Combined, TikTok and Douyin represented the third-largest social media platform in the world by monthly users, behind only Facebook and Instagram.
Why Competitors Struggled to Respond
Meta the company behind Facebook and Instagram invested billions into Reels, its short-form video feature, as a direct response to TikTok's growth.
Internal documents that surfaced through a whistleblower in 2021 showed that retaining younger users had become a stated priority for the company.
The fact that a well-resourced competitor felt compelled to rebuild significant parts of its product around TikTok's model says something about how completely TikTok had shifted the social media landscape.
Conclusion
TikTok became genuinely popular in stages building through 2018 and 2019, then breaking into the mainstream in 2020. The pandemic accelerated what was already happening. As reported by CNBC, TikTok confirmed reaching 1 billion monthly active users in September 2021 a number that settled the question of its place in social media history.
Frequently Asked Questions
Was TikTok popular before Covid-19?
It was growing steadily. By 2019, TikTok had 1 billion total downloads and was the fourth most-downloaded non-gaming app in the world. But mainstream cultural popularity — across age groups came in 2020.
When did TikTok become popular in the United States?
TikTok began gaining serious traction in the US in 2019, primarily among teenagers. Broader mainstream adoption came in 2020, when the platform gained over 100 million US monthly active users during the Covid-19 pandemic.
When did TikTok hit 1 billion users?
TikTok reached 1 billion monthly active users in September 2021, making it the fastest social media platform to reach that milestone.
What is the difference between TikTok and Douyin?
Douyin is the Chinese version of the same app, operated separately under different content moderation rules. TikTok is the international version. Both are owned by ByteDance.
How did TikTok become more popular than Instagram?
TikTok surpassed Instagram in downloads in 2018. By 2022, it was also competing with YouTube on time spent per user. The primary driver was its algorithm, which gave any video the chance to go viral regardless of the creator's follower count.