Influencer marketing (also influence marketing) is a form of marketing that has emerged from a variety of practices and studies, in which focus is placed on specific key individuals (or types of individual) rather than the target market as a whole. It identifies the individuals that have influence over potential buyers, and orients marketing activities around these influencers.

Influencer content may be framed as testimonial advertising where they play the role of a potential buyer themselves, or they may be third parties. These third parties exist either in the supply chain (retailers, manufacturers, etc.) or may be so-called value-added influencers (such as journalists, academics, industry analysts, professional advisers, and so on).

The first approach to that theory comes from a communication classic, The People´s Choice (Lazarsfeld and Katz), a 1940 study on political communication that was also known as Multistep flow model, that claims that the majority of people are influenced by secondhand information and opinion leaders.

Lee Oddon of Top Rank Marketing explains that Influencer Marketing “develops relationships with internal and industry experts with active networks to co-create content that helps drive measurable business goals.”