Wikipedia: User innovation refers to innovation by intermediate users (e.g. user firms) or consumer users (individual end-users or user communities), rather than by suppliers (producers or manufacturers).
Eric von Hippel and others observed that many products and services are actually developed or at least refined, by users, at the site of implementation and use. These ideas are then moved back into the supply network. This is because products are developed to meet the widest possible need; when individual users face problems that the majority of consumers do not, they have no choice but to develop their own modifications to existing products, or entirely new products, to solve their issues. Often, user innovators will share their ideas with manufacturers in hopes of having them produce the product, a process called free revealing.
Based on research on the evolution of Internet technologies and open source software Ilkka Tuomi (Tuomi 2002) further highlighted the point that users are fundamentally social. User innovation, therefore, is also socially and socio-technically distributed innovation. According to Tuomi, key uses are often unintended uses invented by user communities that reinterpret and reinvent the meaning of emerging technological opportunities.
see also unintended use, repurposing, kluge