Influencers and marketers must clearly disclose their relationships, the Federal Trade Commission reiterated in more than 90 letters sent by the agency after it reviewed social media posts by celebrities, athletes and other influencers.

The letters were “informed” by petitions filed by Public Citizen and mark the first time the agency has reached out directly to educate social media influencers themselves, the FTC said. Each of the letters cited a social media post that concerned the agency, which expressed the desire to educate the recipient about existing standards.

“The FTC’s Endorsement Guides state that if there is a ‘material connection between an endorser and the marketer of a product—in other words, a connection that might affect the weight or credibility that consumers give the endorsement—that connection should be clearly and conspicuously disclosed, unless the connection is already clear from the context of the communication containing the endorsement,” wrote Mary K. Engle, associate director of the FTC’s Division of Advertising Practices. “Material connections could consist of a business or family relationship, monetary payment, or the provision of free products to the endorser.”

To be “clear” and “conspicuous,” the disclosure should use unambiguous language and stand out, the FTC advised, so that consumers can easily notice the disclosure and not have to search for it.

In an example specific to one social media platform, the agency noted that consumers who view posts in their streams or on mobile devices typically see only the first three lines of a longer post unless they click “more,” which many consumers do not do. “Therefore, an endorser should disclose any material connection above the ‘more’ button,” Engle wrote. “In addition, where there are multiple tags, hashtags, or links, readers may just skip over them, especially where they appear at the end of a long post.”

Some of the letters addressed particular disclosures that the agency declared “not sufficiently clear,” such as “#sp,” “Thanks [Brand],” and “#partner.” “[M]any consumers will not understand” that such a post is sponsored, the FTC said.

For marketers, the FTC also suggested that they review their written social media policies to ensure compliance with the Endorsement Guides (or implementation of such a policy if they lack one) and conduct an appraisal of their social media marketing to ensure that all posts contain the necessary clear and conspicuous disclosures.

To read a sample letter to an influencer, click here.

To read a sample letter to a marketer, click here.

Why it matters: The letters serve as warnings to influencers and marketers that the FTC is keeping a close eye on social media to ensure compliance with the Endorsement Guides. The agency emphasized three important tips: Keep disclosures unambiguous (avoid vague terms that won’t explain the nature of the relationship between an influencer and the brand), make disclosures hard to miss (by disclosing material connections above the “more” button) and don’t bury disclosures in a string of hashtags that readers are likely to skip.