A micro-influencer is a social-media creator with a comparatively small but highly engaged audience — typically defined as roughly 1,000 to 100,000 followers, depending on the platform and source — whose content is concentrated in a specific niche, location, or community.
The category emerged in the mid-2010s as marketers noticed that engagement rates (likes, comments, shares as a percentage of reach) tend to decline with audience size, while the trust and conversion intent of niche followers tend to remain high. The result was a counter-positioning against the celebrity-influencer model: rather than buying one large-audience post, brands began running campaigns with dozens or hundreds of micro-influencers, paying less per slot and tracking aggregate performance.
The model has continued to refine downward — into nano-influencers (under 10,000 followers) and creator-collective platforms — and the underlying logic has spread into adjacent disciplines: word-of-mouth marketing, community-led growth, and ambassador programs all share the structural premise that distributed credibility outperforms concentrated reach for many product categories.