Thorsten Pieper explores the impact of innovation barriers along the user innovation process, in particular whether technological, social, legal and ownership barriers change the properties of user-developed products. This study roots from the "open innovation" research field and reveals insights from innovating users in "collaborative workspaces". The results prove a hierarchical allocation of innovation barriers regarding their influence on the end-product and moderating influences of user innovators' personal characteristics. The author discusses these insights and provides practical recommendations for more efficient promotion of user innovations and successful integration in corporate "co-creation" projects. Contents Identification of barriers in the user innovation process Criteria for distinction of barriers and resource-based problems Analysis of moderating effects of innovators' openness on product properties Target Groups Researchers and students of engineering, technology and innovation management, business engineering and business administration Practitioners in the field of technology and innovation management, product management and product development The Author Thorsten Pieper is project manager and researcher at the Institute for Technology and Innovation Management focusing on open innovation in the field of aircraft industries, agricultural machinery and consumer goods. He graduated at the Hamburg University of Technology with Prof. Dr. Cornelius Herstatt.