Developing and maintaining a user base that actively contributes to an online community is often essential to a website's success. For many online communities, developing such a user-base can be challenge for web designers. Working from a functionalist perceptive, two studies explored how the individual difference of interdependent self-construal was related to participation and engagement in the online community MovieLens.org. In the first study, we found that those individuals high in interdependent self-construal were particularly unlikely to contribute to the website. In an attempt to increase the online engagement of this type of user, we then created an interactive web feature that tapped into the social motives of those high in interdependent self-construal. This feature allows users to create Top Five movie lists that can be shared with other users. In the second study, we found that interdependent self-construal was associated with more use of the Top Five lists feature, that using this feature was associated with more interest in seeing others' lists, which in turn predicted more interest in MovieLens. Implications for web design and psychological theory are discussed.

Administrators of online communities face the crucial issue of understanding and developing their user communities. Will new users become committed members? What types of roles are particular individuals most likely to take on? We report on a study that investigates these questions. We administered a survey (based on standard psychological instruments) to nearly 4000 new users of the MovieLens film recommendation community from October 2009 to March 2010 and logged their usage history on MovieLens. We found that general volunteer motivations, pro-social behavioral history, and community-specific motivations predicted both the amount of use and specific types of activities users engaged in after joining the community. These findings have implications for the design and management of online communities.