for people like sara. social media users with large followers, fashion to fitness, photography, parenting and of course celebrities. >> before social media we relied on traditional medians, like print and broadcast. that forces you to talk at customers. and now with social media you have a opportunity to be part of the consumer dialogue. >> coca-cola is cashing in too, luring selena gomez who can make $550,000 per post were 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've purchased an ie team after seeing an influencer use it on social media, contributing to a billion dollar market this year alone. $5 billion by 2020 according to one forecast. it's money that's funneling down