Digital influencers—popular personalities on YouTube, Twitter, Vine, Instagram and other social platforms—are increasingly attracting a large share of the consumer attention pie and are transforming the rules of engagement with Millennials. A survey conducted for Variety last year concluded that YouTube stars were more influential than mainstream celebs among U.S. teens.

What’s made them so powerful? “Digital influencers” have been around since the dawn of blogging in the early 2000s. However, the accelerated growth of mobile devices and online video has created unprecedented opportunity for this new crop of influencers to reach massive audiences and to engage at a whole new level. Kids and teens are growing up with their phones in hand everywhere they go and with the ability to access content 24/7. The content creators on the other side of the screen make themselves and their content available 24/7, developing a level of intimacy with their viewers that brands and traditional media companies don’t have. The medium of communication—video—is also more personal and engaging than plain text, with the visual and the audio commanding a stronger influence on a viewer’s emotions.

How has the conversation with Millennials changed? In a panel on Digital Stars and Brands during Variety’s Entertainment Marketing Summit, Sam Wick, EVP of business development at Maker Studios, laid out some lessons for brands on building digital influence: (1) create mobile-friendly content; (2) respond quickly; and (3) always be on. Brand marketers traditionally work on a campaign basis, quarterly, monthly, etc., but the voice and presence of digital influencers are consistent and unrestricted to a time period.

Besides mobile-friendliness, responsiveness and accessibility, brands must be authentic. All members of the panel, which was comprised of marketing and media executives and a digital influencer, echoed the importance of authenticity in cultivating the conversation with Millennials. Scott Birnbaum, SVP of marketing at Aeropostale, shared an anecdote from a campaign with YouTube star Bethany Mota. When Aeropostale released a photo of the star that looked overly retouched, her fans on social media were outraged. “Kids can smell fake,” confirms Birnbaum. The great thing about digital is that brands get immediate feedback on the content they put out there, enabling real-time optimization.

So how are forward-thinking brands who target Millennials changing the game? Aeropostale’s relationship with Bethany Mota—a fashion-focused, teenage video blogger with more Instagram followers than Vogue, Cosmopolitan and Glamour combined—began as an endorsement deal. Gaining insight into the relationship between a YouTube star and her fans, Birnbaum realized the opportunity to make that digital influence more tangible and transform it into a lifestyle. Aeropostale worked with Bethany to release her own line of products under the brand. To prevent alienating her fans during this move to commercial, they kept the fans involved in the entire process, creating a sense of ownership that drove brand loyalty.

Another brand creating a sense of ownership among its audience is Marriott. Moxy hotels, Marriott’s new line of boutique hotels for budget savvy travelers, incorporates the concept of the “Global Guestbook,” a curation of social media content generated by individuals staying at the hotels. The Global Guestbook is found online as well as on oversized screens in the hotels, integrating the digital and physical experiences. According to Amy Sherman, head of digital marketing at Marriott, the Global Guestbook lets the audience command and create the “visual identity” of the brand.

From partnering with a digital influencer to embracing user-generated content, companies can more effectively reach and engage Millennials by delivering authentic experiences both online and offline.