The emergence of inclusive and exclusive virtual communities determined by the preferences of their users

Consider the decision faced by the user of a social network site (SNS) regarding whether or not to accept a friendship request from another user. The user making such a decision is constrained by the limited amount of information available about the requester. Therefore, the decision must be based on incomplete information about the main characteristics and preferences describing the requester. We formalize this decision problem by defining the expected utility tradeoffs derived from the request and simulate the resulting acceptance and rejection incentives numerically. These incentives provide the basis on which to build inclusive and exclusive social networks determined by the different expectations and preferences of their users. Social networks are generated using a self-organizing map to cluster the decision makers (DMs) by their friendship acceptance behavior. We analyze the effects on the cluster structure of the resulting social network that follow from modifying the distribution of requesters relative to the preferences of the DMs, the disutility derived from accepting the friendship of an unwanted requester, the costs incurred when searching for potential friends to expand the network of connections, and the minimum networking capacities of the friendship requesters demanded by the DMs.