Not since the heyday of Vine have we seen a social app become an engine for the production of culture the way TikTok is right now. Barely a year old, TikTok is having a moment — and to see it, you don’t even have to open the app.

Open Instagram, or Twitter, or Facebook, or YouTube, and you’re likely to see one of the short, looping videos created in TikTok. The app helped Lil Nas X’s “Old Town Road” rocket top of the Billboard charts, and stay there for a record amount of time. American high schools are starting TikTok clubs to participate in viral dance challenges and other memes.

But the more popular the app has gotten, the more likely it has become that regulators would take notice. TikTok is, after all, owned by the Chinese company ByteDance, and is arguably the first mainstream hit consumer app in America to be made in China. And that’s a fraught position to be in, given the ongoing trade war and growing concern about Chinese censorship of American companies.

As I wrote here in August, in a piece about how TikTok could stumble:

As of today, the US government has taken an interest, requesting an investigation into the app on national security grounds. Here’s Tony Romm and Drew Harwell in the Washington Post: 

TikTok responded forcefully, saying that the company stores data about US users here and in Singapore rather than in China. And it said it would reject any government requests to censor content, including requests from China:

It’s a good statement, written in plain English. And yet somehow I doubt it alone will satisfy regulators.

On the censorship front, there’s evidence that TikTok has been true to its word. Here’s Ryan Broderick doing a little stunt journalism in BuzzFeed:

In any case, regulation isn’t TikTok’s only concern at the moment. It is also beginning to shed users as ByteDance ratchets down the amount of money it’s spending to acquire new ones. (Something else I predicted might happen in August.) Here’s Zheping Huang and Shelly Banjo in Bloomberg:

A final concern for TikTok today: competition. Recently I was talking to a smart person about TikTok who told me that the app had the basic business model of a videogame on Facebook during the heyday of mobile app installs. Developers would determine the lifetime value of a mobile user, then bid less than that amount to acquire them via Facebook. You keep pouring money into Facebook for as long as you can acquire new users for less than you can make from showing them ads. Eventually you run out, the game withers away, and you go make another game and repeat the process.

So far, TikTok has run the same playbook. It knows how much money it can make by showing users ads, and it spends a portion of that money on Facebook, Snapchat, and other platforms to acquire them. But the Bloomberg report above suggests it may be running out of those cheap, early users.

Over the past year, TikTok has had the AI-powered entertainment app market to itself — at least when it comes to apps that have hundreds of millions of dollars to spend on user acquisition. But not any more. Here’s Geoff Weiss in TubeFilter:

Maybe Triller will be the US-based TikTok clone that outgrows the original. Or maybe it just heralds the arrival of a time when AI-based entertainment apps swell in number to the point where customer acquisition gets so expensive that they’re no longer viable.

TikTok is still ascendant in many ways, and it may yet navigate these issues and whatever comes after them. But the road ahead is getting more challenging all the time.

Elsewhere: the Trump Administration can’t decide what to do about Chinese tech; Trump-related TikToks are performing well; this person thinks TikTok is overhyped; the latest trend on TikTok is posting sad voicemails to soundtrack dance videos.