ABC(NEW YORK) -- Crazy stunts, coordinated dance offs and, of course, viral challenges. This is TikTok, the app that’s taking the digital world by storm.

“Nightline” spent time with some of the platform’s most popular creators, including the voice behind one of the app’s biggest hits and the rising stars who are hoping for a breakthrough.

But beyond the lighthearted videos adored by young users who frequent TikTok, serious national security concerns and questions have been raised about the Chinese media company’s data collection and censorship practices.

If you haven’t heard of TikTok, you’re not alone. Reese Witherspoon’s 16-year-old son Deacon had to give her a tutorial.

Witherspoon is just one of the millions of people who have discovered the app, which has been downloaded more than 750 million times in the past year, according to the New York Times.

“Every day you open it up and it's full of different memes or trends you can engage with,” Ryan Broderick, who covers web culture for BuzzFeed, told “Nightline.”

“It's really, really addicting. Its homepage is, like, if you took Facebook’s home page and Netflix’s home page and you made the most addicting combination of the two of them,” Broderick added.

Broderick explained that the content TikTok users make range from cinematic to music videos and beyond.

“It's kind of whatever kids can come up with and that's why it's so exciting -- but also why you can get really crazy, really fast, I think,” he said.

TikTok is especially beloved by teens and young adults, who often engage with new music on the app. The biggest hit of 2019, Lil Nas X’s “Old Town Road,” first blew up on the app.

“Social media was one of the biggest factors in this song’s success,” the artist told “Nightline.” “Social media is the biggest factor in every song nowadays. It's like I use that to my advantage… and it worked.”

“Old Town Road,” which fused hip-hop and country music genres, paved the way for more unconventional breakouts like Blanco Brown’s “The Git Up.”

Brown has been making music his whole life and producing for some of the biggest names in the industry.

“I was always in the background, you know? Afraid to be in the forefront,” Brown told “Nightline.” “The nerves always get me and I really wasn’t the greatest at singing because I [didn’t] have the confidence. So, I mean, like, it’s been a journey.”

Brown wrote “The Git Up,” released his tutorial on the steps to dance along and a TikTok challenge was born.

Brown said he gets “emotional” when he sees people enjoying his music. “I'm holding back tears now, you know, and it's a surreal moment,” he said.

Meanwhile, Ariel Martin, also known as “Baby Ariel,” is used to being a big deal on TikTok. She has nearly 30 million followers on the platform.

“It's a beautiful thing,” Martin, 18, told “Nightline” in Los Angeles. “I just want to express love and positivity and as much as I possibly can because I have this platform.”

“I think everyone is good at TikTok,” she added. “I think everybody can be good at anything.”

Martin was one of the first to build a following on the app, back when it was still Musical.ly.

“I mean, I think…five people following me is a cool thing. A hundred thousand – OK, great. Cool,” she said. “This is my form of creativity and self-expression and I think that everybody who has a form of creativity and self-expression, they should use it as much as they possibly can and go for it.”

Martin is now breaking into the mainstream, landing a role in Disney Channel’s “Zombies 2” and producing her own music.

“Nightline” went behind the scenes for the video shoot for her cover of the song “Wild Side” – the video an ode to acceptance.

A lot of the content on TikTok is created by teenagers like Martin. Bad actors could lurk on the app.

It’s a problem Martin is aware of.

“I think that goes with anything, really, no matter what you do,” she said. “Be safe, tell people what you're doing, where you're doing [it], what you're doing, how you're doing it, where you're going, what you're wearing, and the more we can just be informed on each other and back each other up.”

TikTok says it is working to keep its younger users safe and just released videos made by popular creators that show users how to do things like filter comments, block people and report inappropriate content.

 Kudzi Chikumbu is the director of the creative community at TikTok, and he promotes creators like Drea Okeke, also known as “Drea Knows Best.”

“I am one of those people who's kind of given the mission to make sure that all those creative people stay inspired and creative in a positive and a positive and have a safe place,” Chikumbu told “Nightline.” “As much as it is fun and entertaining, it truly comes from a special place. And [something] like that should always be cherished and held very safe.”

Okeke was awarded a scholarship by TikTok to pursue her masters in entrepreneurship.

“If I see other women of color it's my time now to…bring them up with me, because there's space for all of us,” Okeke told “Nightline.” “Like, come on sis, yes, let's go, like join in.”

TikTok is adamant that the platform is a joyful place, but it is not immune to the perils of the digital world.

According to The Wall Street Journal, TikTok recently had to take down anonymous accounts linked to ISIS, the latest social media company targeted by the terror group.

TikTok deleted the video and banned the anonymous accounts. A spokesperson from the company said “content promoting terrorist organizations has absolutely no place on TikTok.”

The company itself, which is owned by Chinese artificial intelligence startup ByteDance, now faces backlash over allegations of censorship and improper data collection and storage.

There are reports that the U.S. Government has started scrutinizing the company’s data collection and censorship practices amid concerns that TikTok user’s personal data could be made accessible to foreign governments.

TikTok wouldn’t answer questions on camera about this, and instead pointed to a statement on their website by their general U.S. manager.

“At TikTok, we have no higher priority than earning and preserving the trust of our users, partners and regulators,” the statement reads. “We store all US user data in the United States, with backup redundancy in Singapore. TikTok’s data centers are located entirely outside of China.”

The company added that China does not control the content of TikTok in the United States.

“Our US team makes decisions that we see as best for the US market, and we are given the independence to do so,” the company said.

None of these concerns are scaring away brands that are eager to harness TikTok’s influence. Many companies are turning to the app to find the next fresh face and reach its young users.

Cameron Campbell, known on the app as @CamoDancer94, started filming himself dancing at his job at an Indiana Walmart and posting his favorites onto TikTok.

“One of my videos actually went viral,” Campbell told “Nightline.” “I just started blowing up after that and people started contacting me and saying, ‘Would you model for Aeropostale’ and all that stuff.”

Campbell is now one of the newest faces of Aeropostale, which brought him to New York for this photo shoot.

At 25 years old, Campbell creates his TikTok videos on his own. Just over an hour after posting one of his videos, over 14,000 people had watched it.

As is clear in Campbell’s case with TikTok, it can take just 15 seconds to earn your 15 minutes of fame.

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