Blonde, 29 years old and naturally effervescent, Grace Helbig seems as though she belongs on television. Years ago Helbig gave traditional stardom a try, performing at the Peoples Improv Theater in New York City, but along the way she began to make amusing, confessional web videos with a friend, and the clips they posted online soon became much more. “I quickly learned that hustling 100 people into a theater on a Wednesday was way harder than getting 100 people to watch a video on YouTube,” Helbig says.

Before long, she signed a five-year contract with My Damn Channel, a multichannel network (akin to a digital version of media conglomerates such as Fox). It was a decision that proved prescient: Between 2008 and 2013 her YouTube channel gained more than 2 million subscribers. Helbig broke away to launch an independent channel last year; it has since attracted more than 70 million views, and her roundabout trajectory to fame was cemented with The Grace Helbig Project, a comedy talk show that premiered on E! this April.

As YouTube celebrates its 10th anniversary this month, Helbig and a rising class of celebrities on the site are grasping more fame than ever before. Like other famous YouTubers, Helbig found a niche and used her charisma and authenticity to attract legions of fans. And though YouTube celebrities are better known among Internet natives than among their forebears, they now boast a surprising measure of real-world star power, as well as astronomical earnings and leverage with marketers looking to access elusive youth demographics. In other words, with our media landscape fractured across more and more screens, they’re becoming the surest bets mature media brands have of discovering the next Chelsea Handler or Brad Pitt. But can YouTubers ever become truly famous, or will they be forever relegated to B-list status?

“We kind of created Justin Bieber, so we can, absolutely,” says Kevin Allocca, YouTube’s head of culture and trends, with a laugh. Allocca and Helbig emphasize that much of the appeal of celebrities weaned on social media lies in the promise of personal interaction. “YouTube isn’t an art gallery where we put paintings up for people to look at,” Helbig says. “We’re there alongside you, having a conversation.” As Allocca puts it, “The immediacy provided on platforms like YouTube means that authenticity is incredibly important, more important than other types of talent we traditionally associate with stars. To be authentic is a real talent”—one that successful YouTubers such as Helbig have in spades.

Both Helbig and Ryan Higa, another famous YouTuber, say fans in the street stop them constantly. Yet Higa, for his part, denies celebrity status. “I don’t consider myself a big star,” he says. “My fans know my videos, but I’m sure their parents have never heard of me.” The very nature of YouTube makes achieving cross-generational fame difficult. Higa boasts 13 million subscribers, a remarkable number but one that pales in comparison with the number of people who will see ads for a Brad Pitt movie. Moving from YouTube’s depth of fan interaction to the breadth of exposure demanded in mainstream media is difficult. Whether successful YouTubers should want or need to do so is another question; a creator with just 1 million subscribers earns a very comfortable living.

What isn’t in question is YouTube’s unprecedented growth: Venture capitalist Fred Wilson called 2014 the year the platform “became a monster.” Online video consumption is up ninefold since 2010, Americans age 12 to 24 watched 15 percent fewer films in theaters last year than they did in 2013, and a Variety survey found that six of the 10 most popular celebrities among Americans age 13 to 18 were YouTubers, beating out such stalwarts as Seth Rogen and Katy Perry. In response, Hollywood has made huge bets on multichannel networks. Disney paid $500 million to purchase Maker Studios and DreamWorks spent $33 million for AwesomenessTV, while Warner Bros. invested $18 million in Machinima. Even traditional talent agencies such as CAA, UTA and WME have begun directly signing YouTube’s biggest names to weighty management contracts.

Wealth, however, cannot guarantee staying power. “In a world where over two days of video get uploaded every minute, only that which is truly unique and unexpected can stand out,” Allocca said all the way back in 2011. Things have only become more frenzied since, and YouTube’s stars must remain constantly, consistently remarkable. “Given the YouTube dynamic,” says Kenneth Krushel, an assistant professor of media studies at the New School, “where transient oddities are delivered daily with little barrier to entry, and the factor between success and obscurity is alchemy where a presence is noticed as suddenly as it’s forgotten, no, it doesn’t seem that the YouTube stars of today are the enduring stars of tomorrow.”

The greatest barrier between YouTube celebrity and mainstream fame may turn out to be structural. Traditional celebrity is aspirational: People want to be George Clooney. On YouTube, they want to be friends with Grace Helbig. While a talk show works for Helbig because it’s an extension of her YouTube personality, the appeal doesn’t translate to a movie in which she’d play an entirely different character.

Perhaps the largest question looming over the rise of the YouTube generation is whether celebrity itself is changing with them. Jennifer Lawrence rose to stardom in large part because we want to be her best friend; the same argument could be made about Channing Tatum, who is nothing if not the kind of guy who’d be fun at a bar. To borrow a YouTube colloquialism, Lawrence is her “authentic” self. We feel as if we’re her friend, even though we’re not. For Helbig, at least, that authenticity is the engine behind her growing empire. Is authenticity alone enough to make her, or any other YouTuber, the next Lawrence? Only the next 10 years of digital upheaval will tell.