PurposeThis paper aims to manage access control tasks to satisfy the user privacy needs of online information resources according to social relations and tags.Design/methodology/approachThe study proposes a method for access control management in the online social context. The proposed method includes the access control policy management process, metadata of access control policies, the data of ontologies, tags, and social relations, and conflict detection rules.FindingsOnline information sharing and hiding, which needs to consider social relations and mentioned topics, is a unique context and needs a novel access control mechanism. Ontologies are powerful and expressive enough to identify conflicts in access control policies. The paper provides a method using ontologies to control the access control activities based on social relations and tags on web content. The effectiveness of the method's conflict detection rules is validated through several scenarios.Research limitations/implicationsTo make the proposed method suitable for widespread usage, further work is required to develop an access control policy specification and conflict detection tool. The proposed method introduces relatively novel usage scenarios, which consider social relationships, and tags compared with existing access control methods for online information sharing.Practical implicationsThe proposed access control mechanism can be integrated into existing web sites. Online users can use this method to share information more easily than at present.Originality/valueThe method enables flexible access control in social contexts and handles unavoidable conflicts. It also opens the way to new access control scenarios in online social activities. The method can be used to keep secrets hidden from selected people.

Information overload and privacy protection become critical issues with blogs. This paper presents the ontological subscription and blocking system (OSBS) using policies, ontologies, and rules to subscribe interesting posts and block unwanted posts. This system also uses rules for automatic conflict detection between polices. The effectiveness of two subscription systems, OSBS and RSS (rich site summary) reader, is compared. The experimental results reveal that the perceived privacy benefits on the novel OSBS are better than the existing RSS reader. The novel OSBS is as good as existing RSS reader from perceived information overload alleviation perspective.