Moj Mahdara’s “aha” moment came when the ambulance pulled up at last year’s BeautyCon convention.

Young girls, lined up for hours to meet and spend some time with YouTube and Instagram personalities, were wilting in the heat.

“There were over 10,000 girls that showed up and waited in line for six hours last August in the heat,” she said. “That’s a sight you don’t see for anything other than Justin Bieber. This was madness.”

Mahdara’s Hollywood marketing firm, Made With Elastic, had just bought the BeautyCon conference, and rather than promote it by hiring expensive celebrities and putting on a costly marketing campaign, Mahdara took a viral route and used Internet stars.

Mahdara, MWE’s chief executive, said watching the girls wait in line for hours made her realize that bringing brands together with Internet personalities could help create a new marketing channel.

“Previously, brands or marketers wanted to work with like a Robert Downey Jr.,” she said. “But now, they want to work with people that have more of a digital footprint.”

BeautyCon, a one-day event featuring presentations, how-to makeup booths, parties, and opportunities to preview and shop new beauty and makeup products, will make its New York debut in two weeks, using the same strategy of employing online personalities.

Kandee Johnson, a former celebrity makeup artist turned YouTube star, has participated as a guest speaker since the convention launched and was there when the ambulance rolled up at last year’s event.

“It was insane,” she said of the long lines outside the event. “I mean I went outside to hand girls water because I felt so bad.”

Johnson, who will be a speaker at the New York event, is the kind of Internet celebrity whose credentials pull in attendees. What started as a hobby to teach makeup tips and tricks has become a full-time job that supports her and her three young children.

“It’s more than a full-time job,” said Johnson. “From the morning when I wake up, I’m sending out tweets. I’m reading emails. I’m replying to people. I’m doing a Facebook post, an Instagram post. I’m writing a blog. I’m filming a video. I’m editing it and I’m posting it to Snapchat and back to Facebook.”

She said she’s often up until 3 a.m. creating content for the more than 3 million followers she has across various social media platforms.

That’s the kind of following Mahdara was looking for when it came to choosing participants for BeautyCon. The online personalities not only help sell tickets, they increasingly have appeal to advertisers and sponsors.