Rosta Farzan

Increasing commitment to online communities by designing for social presence

The existence and survival of online communities depends upon the commitment and retention of their members. This paper compares alternative ways of designing online sites to increase member commitment. We report the results of two experiments conducted within a Facebook game application. The results show that designs can increase commitment and retention of players either by visually highlighting individual members, or by emphasizing the community as a whole. These designs influence commitment through different routes.

Encouraging user participation in a course recommender system: An impact on user behavior

User participation emerged as a critical issue for collaborative and social recommender systems as well as for a range of other systems based on the power of user community. A range of mechanisms to encourage user participation in social systems has been proposed over the last few years; however, the impact of these mechanisms on users behavior in recommender systems has not been studied sufficiently. This paper investigates the impact of encouraging user participation in the context of CourseAgent, a community-based course recommender system. The recommendation power of CourseAgent is based on course ratings provided by a community of students. To increase the number of course ratings, CourseAgent applies an incentive mechanism which turns user feedback into a self-beneficial activity. In this paper, we describe the design and implementation of our course recommendation system and its incentive mechanism. We also report a dual impact of this mechanism on user behavior discovered in two user studies.

Fresh faces in the crowd: turnover, identity, and commitment in online groups

Turnover is commonplace in many online groups because of low barriers of entry and exit. In offline settings, turnover can have a negative impact because of reduced attachment to the group as an entity. However, in an online setting, turnover in terms of changes in the visible membership of a group may have a very different impact. Online only a limited amount of information about members and their activities is observable; in particular, it is easier to see the behavior of the subset of members who are active than the potentially larger set who are not. In this paper, we describe an experiment examining the influence of visible membership turnover on commitment to an online group. Our results suggest that increased turnover in an online group may increase social presence, creating perceptions of liveness, in turn leading to increased levels of participation in the group. However, this result holds primarily for groups with a common identity, suggesting that attention to behavior of others may be stronger when people share an identity with those others. Our results extend understandings of attachment in an online setting as well as theory about social tuning.

Social Search in the Context of Social Navigation

The explosive growth of Web-based educational resources requires a new approach for accessing relevant information effectively. Social searching in the context of social navigation is one of several answers to this problem, in the domain of information retrieval. It provides users with not merely a traditional ranked list, but also with visual hints which can guide users to information provided by their colleagues. A personalized and context-dependent social searching system has been implemented on a platform called KnowledgeSea Ⅱ, an open-corpus Web-based educational support system with multiple access methods. Validity tests were run on a variety of aspects and results have shown that this is an effective way to help users access relevant, essential information.

What Influences the Decision to Participate in Audience-bounded Online Communities?

Building online communities to support small, audience-bounded offline social structures such as neighborhoods or organizations can be challenging. Due to the small size of their potential audience, the contribution volume is likely to be insufficient to maintain a sustainable community-driven system. In our research, we are interested in studying how different characteristics of the offline structure of these communities can influence their online behavior. Particularly, we analyzed participation of researchers in a social system for conferences. Our analysis shows that centrality in the academic social structure is a significant predictor of the likelihood to accept an invitation to participate in the system. These results suggest that an understanding of the users’ offline context can increase the effectiveness of user engagement strategies in an online context.

CTS 2012 tutorials

These keynote speeches discuss the following: security of cloud computing, storage, and networking; P2P networks: file sharing to collaborative computing and data fusion; trust networks; collaborative document management and knowledge work; socialization of newcomers in online communities; models of coordination in multiagent decision making; introduction to complexity in collaborative environments.