Social interaction history refers to traces of social interaction in information spaces. These traces have potential to help users explore and navigate through information spaces. In digital spaces, however, past records of social interaction are often hidden or underutilized. As a result, users cannot use social navigation to guide their movement while browsing information collections. We developed a conceptual framework for using social interaction history to improve information exploration. The basic hypothesis of our framework is that social interaction history can serve as a good indicator of the potential value of information items. We tested our hypothesis by performing statistical analysis of a data set from a social Web application. The results supported our hypothesis: there were significant positive relationships between traces of social interaction and the degree of interestingness of Web articles. We discuss the implications of these findings for the design of social applications and the potential applications of social interaction history in various domains.