"They're not letting anyone else in!"

The besotted line of mostly tween girls and their mothers appeared to take that news as unreliable and decided to stick it out, despite a drenching cold rain blowing sideways on 34th Street.

This is not the usual crowd for a NewFront, upfront or any other spring ad sales ritual, but this is what went down before (and likely during) YouTube's show Wednesday night at the Theater at Madison Square Garden.

That line snaked into building and down a velvet rope to a tiny woman standing on a stage in front of a screen: 18-year-old budding style mogul Bethany Mota. Those lucky enough to reach the end of the line got to exchange a few words with Ms. Mota and a hug.

Why were they there? Possibly because Ms. Mota told them to in a tweet four hours earlier:

Can't wait to meet u guys at MSG in a few hours! Who's planning on coming? :) 💕

— Bethany Mota ∞ (@BethanyMota) April 30, 2014

Fully aware of the suffering going on outside the building, Ms.Mota re-tweeted messages from the line and tweeted back words of encouragment:

@BethanyMota waiting on line to see beth CANT WAIT😃😃👌😱😱😄😄😃😃😜😜😜😝😝😝😝😝😃😃😃SO EXCITED ILYSM BETHERS 💕💕💕💕💕💕💕💕😝 pic.twitter.com/KnXPqVIZbQ

— FollowMeAri TysmBeth (@emily13_a) April 30, 2014

"@ssxo___: Waiting for u !!! Love u 😘😘😘😘 @BethanyMota pic.twitter.com/QTWBs8YXPw" omg ❤️ stay warm! See u soon!

— Bethany Mota ∞ (@BethanyMota) April 30, 2014

More than anything else said by new YouTube CEO Susan Wojcicki, content chief Robert Kyncl or anyone else onstage at YouTube's third "Brandcast," this is the impression YouTube wanted the 2,000-odd brand and agency execs attending to walk away with: You may not have heard of Bethany Mota, but she is a big, big star born, bred and native to YouTube. (Seventeen pitched its web video this week with a similar emphasis on native YouTube stars.)

This year, YouTube positioned its role as curator, and for the most part turned the show over to content brands like Ms. Mota, who disarmingly told the story of how she made her first video after being cyber-bullied at age 13. Vice co-founder Shane Smith gave his pitch for a "changing of the guard" in news and information.

"We're not the next CNN," he said, "we're going to be 10-X CNN."

Other YouTube brands featured in what was an upfront-inside-an-upfront included cooking and lifestyle content producer Tastemade, Soul Pancake, DanceOn and Red Bull. Highlighting the big-budget nature of these events, Janelle Monae performed and Pharrel closed the show with "Happy," but not before thanking YouTube for giving the song "ubiquity" and turning it into a hit.

YouTube's strategy for the past three years has been about investing hundreds of millions of dollars in new channels; now, the company is investing in building up the brands, putting the visage of Ms. Mota and others on bus shelters, airline seat-back pockets, billboards and TV ads. It's a more-than subtle shift designed to make YouTube brands better known off YouTube, and more likely to register in the minds of advertisers.

"What you have seen so far is just the beginning," said content chief Robert Kyncl, who introduced a new channel from DreamWorks, which acquired YouTube network Awesomeness TV this time last year. It's called DreamWorks TV, a family channel that will make content expressly for YouTube and will arrive this summer.

YouTube also pitched its "preferred" bundle of channels, which it is offering to TV advertisers on a guaranteed basis. In a break from the past, YouTube is gating off the high-gloss content and allowing advertisers to buy it exclusively, as well as guaranteeing delivery in various demographics. They've also substantially cut prices, one advertiser said, making YouTube a much cheaper alternative than TV.

As is tradition at these things, YouTube got a brand testimonial, this time from PepsiCo CMO Frank Cooper, who said that while Pepsi has worked successfully with celebrities like Michael Jackson, Madonna and Beyonce, the next celebrity will just as likely come from YouTube.

"We recognize that the next generation of influencers changing pop culture will be very different from those stars," he said.