Forget 15 minutes of fame on the Internet–six seconds will do.

That’s the maximum length of a video on Vine, the social media app that lets users capture and share looping short films–and is spawning an entire crop of celebrity names unlikely to ring a bell with anyone over 18.

There’s high school friends Jack Gilinsky and Jack Johnson of Vine duo “Jack and Jack.” In a fit of boredom a year ago, the two posted a clip called “Nerd Style Vandalism.” They dressed up in thick rimmed glasses and buttoned up shirts, and on Gilinsky’s family SUV wrote “= 16” after the car’s “4X4” logo.

Now, they have 3 million followers on Vine. They’ve called off plans for college this fall, and armed with a hit single on iTunes, the two began an 18-city concert tour this past weekend that’s sold more than 100,000 tickets.

Their die-hard fans: tweens and teens who are more likely to get their cues from Vine and YouTube than what’s on primetime TV. Youth between the ages of 12 and 17 watch fewer hours of traditional television than any other age group; and the figure has declined 7 percent in the last five years, from 104 to 96 hours per month, according to a Nielsen report from the first quarter of this year.

At the same time, more than 75 percent are on Facebook and 25 percent on Instagram, according to the Pew Internet & American Life Project.

Analysts and some industry executive say that between Vine, YouTube and videos on Instagram, the under-18 crowd’s viewing habits portend a radical shift for television and traditional models like the cable bundle, which is already under threat from the Internet.

“Children are predictors of the future and after they spend years forming habits, they don’t miraculously change habits just become they become older,” said David Pakman, an investor at Venrock, a venture capital firm that has invested in social media companies.

Teens said they identify more with YouTube celebrities such as comedians Ryan Higa and Smosh, a “Saturday Night Live”-style singing, rapping duo, more than Hollywood A-listers Jennifer Lawrence and Seth Rogen, according to a July poll commissioned by Variety Magazine.

And like YouTube, Vine, which is owned by Twitter and has 40 million registered users, is producing celebrities who are getting increasingly picked up by mainstream media.

After the folk pop duets of Michael and Carissa Rae Alvarado went viral on Vine last year, the singers, who are married and known as Us The Duo, were picked up by Republic Records, the record label that represents big stars including Nicki Minaj and Jessie J.

Vine also introduced the world to Jeffrey Eli Miller, a 13-year-old baby-faced Boston area middle schooler, who has been compared to Justin Bieber. With a braces-filled wide grin, his 6-second soulful cover of a Beyonce song in May drew 1.2 million followers and landed him on “Good Morning America.”

Vine, which is based in New York, was founded by Dom Hofmann, Colin Kroll and Rus Yusupov in June 2012. Hofmann, who left the company late last year, told Wired that at first they tried different time limits for Vine videos, ranging from five seconds to ten seconds. Then they added a loop to make things more interesting. Four months after the company was founded, it was acquired by Twitter–before the product had even officially launched.

Vine quickly caught on–and not just with teens. A user uploaded a short looped video of the Boston Marathon bombing in April 2013 that became iconic.

The app has also been used to show the recent protests in Ferguson, Mo. And companies such as Dunkin Donuts have capitalized on the format for their ad campaigns.

It’s not clear if Vine makes any money. Twitter, which went public last year, does not break out viewers or business metrics for Vine in its public filings. There are no ads on Vine, and Twitter won’t comment on how it plans to make money with the app.

“We’re solely focused on users and providing the best possible experience,” said Carolyn Penner, a spokesperson at Twitter.

Vine has rated the app for users 17 and older, but many users are far below the suggested age restriction. The company won’t disclose the ages of its users. But its popularity is particularly fueled by tweens and teens, Internet investors and analysts say. Young mobile phone users are flocking to apps that help them discover new personalities, music and fashion shared by their peers and not handed down through glossy marketing campaigns.

Vine can feel like the highlights reel from MTV’s JackAss, “What Not to Wear” and an open mike at the county fair. The six-second limit for clips forces video creators to tell a story, joke as efficiently as possible.

And it differs from YouTube and Twitter, which are still the preferred platforms for big celebrities such as Kim Kardashian and Justin Timberlake. When tweens get their first smartphones — and a majority of middle schoolers now owns one of the devices — they are still most influenced by peers and are relatively new to the celebrities showcased on Jimmy Fallon’s Tonight Show or in Hollywood blockbusters.

It’s too soon to forecast the end of Hollywood–after all, the Bieber phase spawned by YouTube passed in a flash. But as with Bieber, the new stars of the social networking apps are attracting entertainment industry opportunists, including record labels, talent agents and advertising executives eager to capi­tal­ize on the latest craze.

Jack and Jack won’t say how much they’ve made as Vine celebrities. They are represented by United Talent Agency and were headliners at the pre-party of the Teen Choice Awards hosted by DigiTour, which runs events attended mostly by teen and tween girls and regularly sells out 2,000-seat venues.

“We came from the traditional side of the music business and saw things were really changing,” said Meridith Valiando Rojas, a DigiFest co-founder who recruited Jack and Jack for events. “Teens were spending more time on mobile devices and social networks versus radio or watching TV and they were forming intimate fan relationships online.”

The two Jacks — one brunet, the other blond — don’t want want to be pigeon-holed as one-hit wonders of six-second comedy. Wise to the formula of social media success, the two know their continued success depends on staying relevant by continuing to post Vines, photos on Instagram, YouTube videos, and tweets to promote their appearances.

“We want to cover the whole spectrum, like Justin Timberlake,” Gilinsky said in a phone interview . “Like he’ll be in a movie and have a number one song.”

For Vine’s stars, Bieber is the model for success. Despite a recent run of controversy and bad publicity, in 2013 he made about $80 million in ticket sales, merchandise and all the other opportunities that come with stardom, according to Forbes.

Bieber has also fueled an industry of Vine talent managers and agents hoping to discovering the next social media star.

When Jeffrey Eli Miller uploaded a cover of Beyonce’s “XO”, Vine’s editors found the clip and promoted it on their home page. The clip quickly got 600,000 likes and revines. Soon, talent scouts reached out online and Miller set up a business Gmail account that his parents carefully vet for unscrupulous offers.

It’s made for a surreal summer for the soon-to-be eighth grader. Miller, with an sweet tenor voice, gets embarrassed when he’s compared to Bieber.

“I don’t know what to say about that. I’m Jeffrey,” he says, laughing.

He’s was shocked to see thousands of screaming fans — some with signs with his name — and the recent “meetup” for Vine stars in San Diego.

Jeffrey wants to do “this” — the quest to become a social media-to-mainstream crossover star — “for a living,” said his mother, Cynthia Miller.

Meanwhile, DigiTour Media’s Rojas is already looking at new platforms. There’s Instagram — the photo-sharing site that’s particularly popular among young girls — as well as Snapchat, a social media app where photos disappear seconds after being viewed.

Are disappearing social media stars the next step? It may defy logic, but Rojas think it has a chance.

“I have my eye on SnapChat,” said Rojas. “It will do interesting things.”