It's word-of-mouth marketing at its purest, a cost-effective way to spread brand messages and generate buzz.
But as video-sharing sites become saturated with mediocre content - and media giants crack down on copyright infringement - will viral videos retain their initial impact?
"I think they're actually becoming more popular," says Tony Obregon, director of social media in Cohn & Wolfe's San Francisco office. "Businesses are realizing that it's not so much about advertising. Viral videos are more about entertainment and connecting ...