Most often, 40 percent of the time, the videos were traditional advertisements. Others were "guides," in which a host showcased a particular alcohol, discussing its merits and offering serving suggestions. Some (10 percent) featured men showing off their "chugging" prowess.
There is no way of knowing how many of those millions of viewers were underage kids, according to lead researcher Brian Primack from the University of Pittsburgh.
"Our aim is not to say we should be censoring this," said Primack. "However, knowing about this content should help us develop appropriate educational programs."
The alcohol ads were usually uploaded by "ordinary" YouTube users, rather than manufacturers, according to Primack.
"It didn't seem to be that Bud Light was posting most of these," he said. "It was usually someone who just liked this ad enough to post it."
But the industry is never completely out of the picture, Primack pointed out: Companies create their ads to be funny or otherwise engaging and that may be partly with the hope that people will share them on social media.
"We're not suggesting that young people should never see these videos or that parents say, 'You're never using the Internet again'," Primack said.
Instead, he suggested that parents help their kids be more savvy about alcohol advertising. They could point out how companies can try to manipulate people by, for instance, portraying alcohol as a key ingredient to socializing and having fun.
"Parents can be important purveyors of media literacy," Primack said. "They can help their kids become more critical thinkers about what they see in ads."
The study appears in Journal of Studies on Alcohol and Drugs. (ANI)