More and more companies are pursuing the strategy of actively integrating customers into their innovation development to adequately meet customer needs. Ulrich Bretschneider examines idea communities as a method of customer integration. He first conducts a case study investigation to capture the fundamental characteristics of idea communities. Building on this, he addresses various detailed questions. For example, he demonstrates which motives and personality traits of customers influence the quality of ideas as well as the customers' willingness to contribute ideas.