scouring for people just like samantha who marketers call influencers. social media users with large following whose interests range from fashion and fitness to foe to go fee, parenting, and, of course, celebrity. >> before social media, we relied heavily on traditional mediums like print and broadcast. that forces you to talk at consumers and be the interrupter and now with social media, you really have an opportunity to be part of that consumer dialogue. >> major corporations like coca-cola are cashing in, too, luring mega stars like selena gomez who can make an estimated $550,000 per post, thanks to her 120 million plus followers. >> it's very effective. it keeps that authentic vibe that people like to get when they're on social media. >> some 40% of people say they purchased an item after seeing an influencer use it on social media, contributing to a $1 billion market this year alone, $5 billion by 2020 according to