User-generated content (UGC) is content — photos, videos, reviews, posts — created by everyday customers and creators rather than the brand itself. Brands license or repurpose it because it reads as authentic in a way polished brand content can't, and a whole creator economy now produces "UGC-style" content on commission. For communications, UGC is scalable social proof, and in the AI era its volume and sentiment feed the reviews and mentions engines synthesize when recommending products.