Jalee Baumann, 15, is obsessed with Mariah Carey's, "Obsessed."
The song was released in 2009 and wasn't a terribly big hit compared to the singer's other works. It peaked on the Billboard 100 at No. 7.
But it gained a second life recently on TikTok, where users created and shared choreography for a dance to the track. Baumann gave the dance a shot herself, but it's "Obsessed" that stuck with her.
"Once you're on TikTok all the time, you start to get the sounds stuck in your head and you can just search up the lyrics to find the real song you've been dying to listen to," Baumann said via Twitter messenger. "All of my friends have TikTok, and they find music like me all the time."
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Call it guerrilla radio for the smartphone generation. TikTok's music-infused virality, which traces its origins as an app for lip-syncing along to songs, has made it into an unexpected machine with which young people can discover new songs and artists.
The app now shows up on Spotify and Apple Music, where TikTok-focused playlists have tens of thousands of followers; on YouTube, where songs will often be deluged with comments from users who say they found the song on TikTok; and in the music industry, where some promoters are learning to use the app as a springboard for new music.
But it's not just well-known artists who are benefiting from TikTok. The app played a central role in the ongoing cultural phenomenon of "Old Town Road," a song from rapper Lil Nas X, that is on track to break the record for the longest run in the No. 1 spot on Billboard's Hot 100, which tracks the top songs based on sales, radio airplay and streaming.
Radio long dominated how people discovered new music, making radio stations a crucial juncture in the recording industry. Radio's role in music discovery has even weathered the rise of the internet and streaming services, which reshaped how the industry made money.
But radio is not nearly as popular with younger music fans, according to data from AudienceNet, a consumer research agency. In 2018, it found that Americans ages 16-24 spent far less time listening to music on the radio than older people.
While streaming services do offer some ways for consumers to find new music related to their tastes, TikTok offers something else — pure, crowdsourced discovery.
"When using TikTok, I find a lot of artists and genres of music that I normally wouldn't listen to," Nicole Fiala, 17, of Las Vegas, told NBC News via Twitter messenger. "With Spotify, I normally listen to songs and artists that I already knew of, or music very similar to what I'm comfortable with. With TikTok, it's more diverse."
Music has always been a key part of TikTok, tracing back to its origins as a lip-syncing app called Musical.ly. After the app was acquired by Chiniese tech company ByteDance in 2017, the company rebranded it as TikTok in 2018, but kept the format of the app mostly the same.
But the app is not geared for users to consume music, instead using popular tracks as a way for people to have a common thread through their posts. So, Fiala and many other users turn to streaming services and YouTube, which are now showing signs of TikTok's ability to push people to new music.
"On Spotify ... you can search for playlists, and I listen to a playlist called, 'tiktok songs that are stuck in my head,'" Fiala said. That playlist has well over 100 songs and almost than 87,000 followers on Spotify.
YouTube has its own Tik-Tok scene. When videos of people putting cotton swabs in their mouths to singer-rapper Lizzo's "Truth Hurts" became a TikTok sensation, the video's YouTube page reflected it.
"Who's from tiktok too?" one person posted.
"50% of the comments are people from TikTok," another person posted.
The wave of people heading from TikTok to music streaming apps has not gone unnoticed by some in the music industry who see an opportunity.
Michael Pelchat, 21, who goes by @NiceMichael on TiKTok, was the first person to upload "Old Town Road" to the app in order to film himself dancing in cowboy clothes to the song.
"I was on Twitter, and I was just scrolling through, looking at stuff and I saw this 5-second audio, like, a 5-second video of someone doing some stupid stuff, but that song was in the background. It was just the, 'I got the horses in the back,' and I was like, 'I need to find this song,'" Pelchat said.
A portion of Pelchat's income now comes from promoting songs on TikTok. He works with Muuser, an influencer marketing agency for music that acts as the middleman between record labels and TikTok stars. For each song he promotes, Pelchat said he can make between $300 to $600. Some of his recent promotions include the Black Eyed Peas' "Be Nice" and Maxo Kream's "She Live."
"TikTok is an audio platform, whereby video is the medium used to express interest in the sound," Max Bernstein, founder of Muuser, said. "On TikTok, if you're interested in a sound, you make a video to it, and the focus is on the sound,"
There's no guarantees or formula for success on TikTok, according to Bernstein, and while there is some form of curation as to what songs are being pushed by record labels on the app, it's the users who decide what tracks make it big.
"To the extent that a record label can manufacture some kind of viral success is everyone's goal, but it's not like the whole community is curated by the music business," Bernstein said.
Some record labels have seen the success of music on TikTok and have skipped the middleman to focus directly on buying ads on the app to market their artists.
Teenear, a singer with Miami-based Slip-N-Slide Records, encouraged her label to promote her song "I LIke It" on TikTok.
"Once she told me about it, I had to investigate. It's perfect," Slip-N-Slide CEO and founder Ted Lucas said. "Maybe even six months ago, we wouldn't be on TikTok but today … songs are going viral."
From its early days, Teenear said she felt TikTok would become a place where artists could market their songs in an organic way to younger audiences, and said "I Like It" has continued to grow thanks to the platform.
"It's younger adults and kids that I want to gravitate to. If they hear the song by somebody that they look up to, whether they like it or don't like it, they're going to hear it, so I think TikTok is a great way to get my song out there," Teenear said.