A sponsored post is content a creator is paid (in cash or product) to publish promoting a brand. Under FTC rules it must be clearly disclosed — #ad or #sponsored, conspicuously placed — because the audience has a right to know the relationship. Sponsored posts are the core unit of influencer marketing; their effectiveness hinges on fit between creator and brand, and on disclosure that builds rather than erodes trust. Undisclosed sponsorship is both a legal risk and a credibility risk.