This paper describes the findings from a summative evaluation of an innovative, interactive, digital teaching resources library in sociology (TRAILS). The purpose of TRAILS is to increase the usage and diffusion of cutting-edge teaching and learning materials to a more diverse audience as well as to increase the network activities of TRAILS users. The evaluation tests theoretical models of diffusion of innovations and unanticipated gains from network participation. The evaluation's purpose is to measure the effects of TRAILS by testing a series of hypotheses about changes in the scope and diversity of TRAILS users, and the density and diversity of a network of teaching and learning materials producers and consumers. The evaluation uses a quasi-experimental design to examine the changing demographic and institutional characteristics of TRAILS users and the increases or decreases in users' network activities. It provides a generalizable model for evaluating the effects of teaching and learning innovations. #2011Conference #SocialNetworkAnalysis #AssessmentinHigherEducation #Prek-12EducationalEvaluation