In times of demographic change, skill shortage, and disrup- tive innovations, organizational knowledge and innovative capacity are the key to a company’s success. But how can knowledge be retained with fast staff-turnover, global project-based work and parental leaves? Using social networking sites to improve knowledge dissemination at work seems promising, when looking at the success of private social net- working sites. In this article we investigate how user diversity influences the motivation to use such a site at work. We conducted a survey in a company that successfully implements social networking for knowledge dissemination (n = 50) and analyzed differences in usage motivation using multiple linear regression analysis. Among other effects, we found that women use such a system because of a stronger need for social interac- tion and information. From our findings we derive practical implications for designing a social networking site for work.