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If you're looking for videos of strange bears riding motorcycles or dogs lip-syncing to heavy metal, let me introduce you to a little app called TikTok.

The video-sharing app, launched internationally by Beijing-based startup ByteDance in 2017 following the success of a Chinese version called Douyin in 2016, has become astoundingly popular in a very short period of time. Data from research firm Sensor Tower shows that it's been downloaded more than 750 million times over the past 12 months--more than Facebook, Instagram, YouTube, or Snapchat.

Most of that newfound popularity comes from American teenagers. My own experience as a high school athletics coach confirms this: I've seen more TikToks in the past year on team messaging threads than I ever expected or care to admit. (Hey, some of the kids make very funny videos.)

You might guess that a brand-new app taking over the social media world might ruffle incumbent feathers--and you'd be right. On Sunday, the New York Times reported that Facebook, Google, and Snap are all fighting hard against the Chinese platform's American incursion. Here's the interesting part: They're trying all of the classic crush-the-upstart strategies--copy, acquire, and discredit--so far without much success.

First, copy: Facebook once hugely succeeded by building Snapchat's core function into Instagram's now-ubiquitous Stories feature. Its TikTok-focused attempt--a similar app called Lasso--hasn't experienced nearly the same amount of traction.

Next, acquire: Google recently approached a TikTok competitor called Firework about a potential acquisition, according to the Times. The search giant ultimately decided against it--it's unclear why--opting to try building TikTok-esque functionality into YouTube instead. But the acquisition threat still exists, especially for a company with such financial resources as Google.

Finally, discredit: Just last month, Mark Zuckberberg criticized his Chinese competitor by noting how few TikTok videos of the recent Hong Kong protests existed, especially compared to content on Facebook-owned WhatsApp. "On TikTok, the Chinese app growing quickly around the world, mentions of these protests are censored, even in the U.S.," he told students at Georgetown University. "Is that the internet we want?" (ByteDance has pushed back on that assertion, telling the Times on Sunday that the Chinese government doesn't censor TikTok's content.)

The playbook isn't working, partially because ByteDance isn't an average startup. Founded in 2012 by Chinese entrepreneur Zhang Yiming, now 36, it's become the largest private tech company in the world--valued at $75 billion, according to market research firm CB Insights. And TikTok isn't even ByteDance's core product. That's Tautiao, a personalized content aggregator that adapts to user preferences through machine learning.

Another reason Facebook and Google can't seem to defeat TikTok: It can be shockingly easy to gain widespread popularity on the platform. In August, Rolling Stone wrote about how TikTok's recommendation algorithm prioritizes brand-new clips just as much as those from established users, which means anyone can theoretically make a video that gets seen by millions. The allure is powerful.

Perhaps the most important reason: TikTok has tapped into the zeitgeist. One person starts using it, followed by their friends, and then all of their friends too. Nobody wants to miss out--especially teenagers.

After all, FOMO is one of the world's most powerful customer acquisition forces. Don't ever bet against it.