by 
The millions of people who follow Kim Kardashian West and her sisters on social media have become accustomed to seeing them praise everything from fat-burning tea to gummy vitamins for healthier hair.
“Ever since I started taking two @sugarbearhair a day, my hair has been fuller and stronger than ever!! Even with all the heat and bleaching I do to it!” Khloé Kardashian posted on Instagram this month.
But in the last week, close watchers of the sisters’ accounts may have noticed a small addition to those laudatory messages about the latest miracle product: “#ad.”
For marketers contending with consumers who use ad blockers online and have cut the cord to their TVs in favor of streaming services, social media has become a way to reach an elusive audience. Brands such as Jack in the Box and Red Bull have proved willing to pay thousands of dollars per social media mention to people like the Kardashians and other so-called influencers who command big, loyal followings on services like Instagram, Snapchat and YouTube.
Captiv8, a company that connects brands to influencers, says someone with three million to seven million followers can charge, on average, $187,500 for a post on YouTube, $75,000 for a post on Instagram or Snapchat and $30,000 for a post on Twitter. For influencers with 50,000 to 500,000 followers, the average is $2,500 for YouTube, $1,000 for Instagram or Snapchat and $400 for Twitter.
The company has counted more than 200,000 Instagram posts a month since January tagged with “#ad,” “#sp” or “#sponsored” — and that does not include those that were not properly marked. Any one brand could be working with thousands of influencers, said Ms. Engle of the F.T.C., and most are not reality television stars.
See more http://www.nytimes.com/2016/08/30/business/media/instagram-ads-marketing-kardashian.html?_r=0