Influencer marketing is the popular practice of using individuals with large social media audiences—known as "influencers"—to advertise products and services through their social media accounts. The Federal Trade Commission (FTC) has made it clear that influencers must clearly and conspicuously disclose their relationships to brands when promoting or endorsing products through social media. To emphasize this point, the FTC sent letters to 90 influencers and marketers earlier this year reminding them of their obligation to make appropriate disclosures on ads. The FTC has also provided Endorsement Guides with answers to frequently asked questions from advertisers, ad agencies, bloggers, and others.

Most recently the FTC hosted a live Twitter chat to answer questions and provide guidance on influencer marketing. The FTC covered a number of topics during the chat, from the use of the hashtag "#ad" as a disclosure to built-in disclosure tools on popular social media platforms. Key takeaways from the Twitter chat are:

• Using "#ad" is a sufficient disclosure, as long as it is hard to miss in the post.

• Even if an influencer posts from abroad, U.S. law still applies if it is reasonably foreseeable that the posts will affect U.S. consumers.

• Built-in tools such as the "Paid" tag on Facebook and "includes paid promotion" mark on YouTube are not sufficient to disclose that a post is an ad.

• For Snapchat and Instagram posts, the FTC suggests superimposing a disclosure over the images. For a series of images, a disclosure on the first image may be sufficient, as long as it stands out, and viewers have time to see it.

The Twitter chat followed shortly after the FTC announced its first settlement with two social media influencers, Trevor Martin and Thomas Cassell, for endorsing the online gambling service CSGO Lotto without disclosing that they were the owners of the company, as well as paying other well-known social media influencers to promote the company without requiring them to disclose the payments in their posts.

Click here to read a transcript of the questions and the FTC's responses during the official Twitter chat.