Common-interest vs. common-bond
Ren, Kraut & Kiesler  describe two groups in terms of social psychology:
- In common-identity groups, members feel more attached to the group as a whole. Identity means that a member feels commitment to a group’s purpose or topic. Seeking and providing information is a primary driver (e.g.: a movie-talk group).
- In common-bond groups, a member feels socially and emotionally attached to particular members as well as to the group as a whole. Here, the focus lies on social interaction (e.g.: pupils who meet after class in a social network).
Both types can coexist: The most active members of an interest-based community may form a bond-based subgroup for instance. And community type can change over time.
The antecedents of common identity and common bond
Antecedents of common identity on a group-level are:
- Social categorization: Very few is needed and people let themselves categorize into groups. Even a random assignment to an arbitrary category will do.
- Interdependence: Four types of interdependence create a sense of group identity: a joint task, a common purpose, common fate, and joint reward.
- Out-group presence: Similar to social categorization very few is needed. A statement implying the existence of other groups to trigger in-group/out-group differentiation successfully.
The antecedents of common bond shift the focus from the group to the individual:
- Social interaction: The frequency of prior interaction is a major determinant of the extent to which people build relationships with one another. As the frequency of interaction between two persons increases, their liking for one another also increases.
- Personal information: Self-disclosure and self-presentation shift attention from the group as a whole to individual members. People are more trusting of those who have a shared acquaintance among their in-group members. So, a friend’s friend is also a friend in cyberspace.
- Interpersonal similarity: People are likely to become close to the extent that they perceive they are similar to each other in preferences, attitudes, and values. In several studies we reviewed, similarity was used to manipulate interpersonal attraction by asking participants to complete a personality and friendship questionnaire, and then telling participants that they were assigned to a group whose members probably would become close friends.
Converging and diverging consequences
In both community types attachment leads members to perceive a group as cohesive and to have a good opinion about the group and its members. It increases participation and the likelihood that the member will remain in the group. But there are also diverging consequences: Both types differ in their effects on
- social loafing (common-bond groups tend to be more tolerant with loafers but members are less likely to compensate for other's under-participation);
- the experience of newcommers (bond-attachment-based groups tend to set up bigger obstacles for newcomers);
- the compliance with group norms (which is stronger in common-interest groups);
- the topics people talk about (engagement in and tolerance for off-topic discussions are more stronger in common-bond groups);
- the amount and type of reciprocity/social exchange of information and support (members with identity-based attachment are more likely to help any member and not just those who have helped them);
- the robustness or salience of community membership (members tend to perceive each other as interchangeable in common-interest groups).
Questions and answers
After having assessed whether one's community is based on interest-attachment or bond-attachment one can now answer the questions of the introductory paragraph:
- Off-topic discussions: In an interest-based community attachment to the group should decrease with discussion drifting away from the core topic. Here, ?-ing on-topic discusions is to the benefit of all members whereas in common-bond communities off-topic chitchat is essential because it offers an opportunity of conveying personal information.
- Growth may be a problem for bond-based groups because attachment should decrease with membership turnover. For common-interest communities - on the other hand - growth is more likely to be benefical.
- Anonymity: Interest-based communities may cope even with a large number of anonymous members, but bond-based communities profit from repeated interaction of its members. This requires that member's actions are visible to each other, that people meet frequently. Public and private communication will also enhance the likelihood of forming ties. These prerequisites are not compatible with anonymity.
Further research: motivation and participation
The distinction between attachment to the group as a whole and attachment to particular members is also decisive in the context of motivation and participation.
Motivation: Dholakia, Bagozzi & Klein Pearo  found that, in general, participants of a network-based VC, where members show identification with the online site itself and not so much with particular members, are more purpose-oriented, they seek information and expect the community to bring them together with others who will provide this information. In small-group based VCs, where members maintain a dense web of relationships with other members and identify with them in the first place, interpersonal connectivity and engagement in social interactions are the drivers of participation. This holds true for business-sponsored communties and for member-initiated communities.
Participation: Yeow, Johnson & Faraj  develop their typology in the context of lurking. Lurking is considered to be either an online form of social loafing or a phase in which the member-to-be learns the community norms by observing the community. The authors distinguish two types:
- Transactional-commerce-oriented VCs are often business-sponsored and the primary driver behind participation is search for and exchange of information (e.g. product support group).
- In relational-interest oriented VCs, the focus lies on relationship and interactions among members. Often, they are initiated by members themselves.
In both types, social loafing motivation as a cause for lurking is more dominant on average but there is a dampend effect within relational-interest VCs: Social learning by observation is more relevant in relational-interest oriented VCs.
Suggestion for further reading
Suggestion for further reading
- For a concise version, see the post "Why knowing your community type is important" on The Community Manager
 Ren, Y., Kraut, R. , Kiesler, S. (200?). Identity and bond theories to understand design decisions for online communities. Google Scholar
 Dholakia, U.M., Bagozzi, R.P., Klein Pearo, L. (2004). A social influence model of consumer participation in network- and small-group-based virtual communities. International Journal of Research in Marketing 21 (2004) 241 – 263. Google Scholar
 Yeow, A., Johnson S.L. , Faraj, S. (2006). Lurking: Legitimate or illegitimate peripheral participation? 27th Conference on Information Systems, Milwaukee 2006. Pre-Publication-Draft