The workload needed for managing privacy and publicness in current social network services (SNSs) is placed on individuals, yet people have few means to control what others disclose about them. This paper considers SNS-users' concerns in relation to online disclosure and the ways in which they cope with these both individually and collaboratively. While previous work has focused mainly on individual coping strategies, our findings from a qualitative study with 27 participants suggest that collaborative strategies in boundary regulation are of additional importance. We present a framework of strategies for boundary regulation that informs both theoretical work and design practice related to management of disclosure in SNSs. The framework considers disclosure as an interpersonal process of boundary regulation, in which people are dependent on what others choose to disclose about them. The paper concludes by proposing design solutions supportive of collaborative and preventive strategies in boundary regulation that facilitate the management of disclosure online.

A mundane but theoretically interesting and practically relevant situation presents itself on social networking sites: the co-presence of multiple groups important to an individual. This primarily qualitative study concentrates on the point of view of individual SNS users and their perspectives on multiple group affiliations. After charting the perceived multiplicity of groups on the social networking site Facebook, we investigated the relevance of multiple groups to the users and the effect of group co-presence on psychological identification processes. Users deal with group co-presence by managing the situation to prevent anticipated conflictive and identity-threatening situations. Their behavioral strategies consist of dividing the platform into separate spaces, using suitable channels of communication, and performing self-censorship. Mental strategies include both the creation of more inclusive in-group identities and the reciprocity of trusting other users and being responsible. In addition to giving further evidence of the existence of group co-presence on SNSs, the study sheds light on the management of the phenomenon. Management of group co-presence should be supported, since otherwise users may feel the urge to resort to defensive strategies of social identity protection such as ceasing to use SNSs altogether or, less dramatically, limit their use according to "the least common denominator". Hence, the phenomenon merits the attention of researchers, developers, and designers alike.

When on the move, cognitive resources are reserved partly for passively monitoring and reacting to contexts and events, and partly for actively constructing them. The Re-source Competition Framework (RCF), building on the Multiple Resources Theory, explains how psychosocial tasks typical of mobile situations compete for cognitive resources and then suggests that this leads to the depletion of resources for task interaction and eventually results in the breakdown of fluent interaction. RCF predictions were tested in a semi-naturalistic field study measuring attention during the performance of assigned Web search tasks on mobile phone while moving through nine varied but typical urban situations. Notably, we discovered up to eight-fold differentials between micro-level measurements of atten-tional resource fragmentation, for example from spans of over 16 seconds in a laboratory condition dropping to bursts of just a few seconds in difficult mobile situations. By cali-brating perceptual sampling, reducing resources from tasks of secondary importance, and resisting the impulse to switch tasks before finalization, participants compensated for the resource depletion. The findings are compared to previous studies in office contexts. The work is valuable in many areas of HCI dealing with mobility.