How Brands and YouTube Stars Are Hooking Up to Reach Millions of Millennials

It wasn't that long ago that marketers thought they were hip to YouTube by posting their TV commercials to the site and eking out a few extra eyeballs. But with the potential now to reach millions and the popularity on social media of video stars like Michelle Phan, more than 150 brands have teamed with an array of talent on Google-owned YouTube and a handful of networks to produce entertaining and engaging ads.

"Creators on YouTube are increasingly crossing over into mainstream pop culture," said Jamie Byrne, YouTube's director of content commercialization. "Most brands are looking at these collaborations as part of a larger campaign or media program."

Google upped the ante last year with Google Preferred, a program that allows advertisers to buy into the top 5 percent of lifestyle and entertainment video on the site, thereby guaranteeing that spots will appear across the most popular channels. The program, which will be promoted as part of Google's NewFronts presentation this week, has served marketers well, according to YouTube executives, with ads averaging an 80 percent increase in recall and brand awareness growing 17 percent.

Here, Adweek looks at how top marketers are engaging YouTube's constellation of stars to build buzz.