"Every month, more than 100 million people watch Vines across the web and there are more than 1 -billion loops every day," said Vine in an August blog post.
This audience is creating its own stars. The biggest Viner, Nash Grier, has accumulated 9.3m followers and more than 900m loops of his videos. By contrast, Justin Bieber, usually one of the biggest stars on social networks, is only the 57th biggest star on Vine with 2.1m followers.
"The recent explosion of Vine stars is unsurprising," says Allan Blair, head of strategy at digital agency Tribal Worldwide.
"YouTube has been the most influential medium for teens and the wider youth audience for quite some time now. Vine is a logical extension of that but with an intensive burst perfect for the increasingly short ¬attention span of Generation Z."
Vine's six-second time limit on videos is seen as one of its creative strengths. "The restrictiveness of the six seconds has also been a driving force for creativity, in the same way as Twitter's 140-character limit," says Damian Collier, founder of Viral ¬Spiral Group, which was one of the first multi-channel networks (MCNs) to sign up Vine stars.
"As a creator, I love how with the time constraint Vine really challenges my creativity," says Vine star Amymarie Gaertner, who has more than 3.1m followers. "With so many categories and ways to showcase users' content, Vine encourages all users to be versatile with their creativity."
It is little wonder traditional media companies are swooping to sign talented Viners. Musician Shawn Mendes is a good example: he signed a deal with Universal Music Group's Island Records in June. That month, his first single sold close to 200,000 copies, and his debut EP in July topped Apple's iTunes chart 37 minutes after being released.
Independent artist Joshua Micah is another success story: he started recording "Six Second Covers" of famous songs, and now has more than 490,000 followers and 31.2m loops of his songs.
In the UK, comedian Dapper Laughs, likened in the ¬Radio Times to offensive dinosaur Roy Chubby Brown, had a top 10 hit on iTunes with his song Proper Moist earlier this year, before striking a deal to front his own dating show on British television channel ITV2.
"I believe he is the new Cilla Black," said the show's executive producer, Dan Baldwin.
Brands are also flocking to work with Vine's big stars. Ford launched its Mustang car in Europe through a Vine campaign devised by Viral ¬Spiral, and Fanta is investing in its own #FantaForTheFunny comedy channel on Vine.
"It appeals to brands because it's a relatively low investment compared with, say, a YouTube video, with a high payoff for success," says Pete Wood, social media director at digital marketing agency 360i London.
"A branded Vine is four times more likely to be shared than a branded video. The platform also has high penetration in youth culture, a notoriously tricky demographic."
"Actors and musicians are no longer your only bridges to reaching a highly engaged audience with your message," adds Elise Bartlett, general manager of marketing agency GrapeStory, which has a number of Vine stars on its books.
"Brands are seeing the value in working with social media celebrities while they are gaining visibility and acclaim, as it tells their younger consumers that the brands understand their tastes as well as the up-and-coming celebrities who are important to them."
Vine has had its share of controversies. Grier was accused of homophobia after posting a clip in which he shouted the insult "Fag!".
The 16-year-old has since apologised for being "young, ignorant, stupid and in a bad place" when he posted the video. Vine has also faced tricky decisions over pornography, banning sexually explicit clips in March this year.
"We don't have a problem with explicit sexual content on the internet. We just prefer not to be the source of it," explained the company.
Copyright has been an issue, too. Prince's label demanded in April last year that it remove clips shot at his gigs.
Meanwhile, this year's Football World Cup popularised the practice of recording clips of goals on TV and sharing them to Vine and Twitter, a practice now being cracked down on by the English Premier League.
"It's a breach of copyright and we would discourage fans from doing it," said a league spokesperson.
"We're developing technologies like gif crawlers, Vine crawlers, working with Twitter to look to curtail this kind of activity."
What next for Vine and its stars, though? Some are exploring ¬other digital platforms, from YouTube - Grier recently signed a deal with AwesomenessTV, the YouTube network owned by Hollywood studio DreamWorks Animation - to Snapchat and Instagram, where there are thriving groups of short-form video creators.
Vine doesn't have ads, so it doesn't earn revenue from clicks, but top Viners are working with brands more, so they will get money to make sponsored clips or feature their products. Some have started to upload compilations of their clips to YouTube, where they can earn ad money.
Live gigs are also a growing source of income for Viners. The Digifest NYC festival in New York last June attracted 12,500 fans, and clips where a Viner spins around to reveal a crowd of thousands of screaming fans at a live event are increasingly common.
But a Viner's core activity remains the app and the website, with its 100m viewers and culture of music, gags and bite-size video-blogging. "Anyone can become a Vine star, it's video for everyone," says Pete Wood.
Allan Blair suggests that talent is the only barrier. "Only the best, most creative minds shine through, making it the perfect breeding ground for those who can go on to greater things."
- Observer