The feeling of connectedness experienced in computer-mediated relationships can be explained by the similarity-attraction effect (SAE). Though SAE is well established in psychology, the effects of some types of similarity have not yet been explored. In 2 studies, we demonstrate similarity-attraction based on the timing of activities—“when-similarity.” We describe a novel experimental paradigm for manifesting when-similarity while controlling for the activities being performed (what-similarity). Study 1 (N = 24) shows when-similarity attraction in the evaluation of connectedness with others. Study 2 (N = 42) identifies an interaction between who-similarity—similarity in personal backgrounds—and when-similarity. Both studies show that real-time computer-mediated interaction can lead to greater feelings of connectedness between people when there is an opportunity to discover when-similarity.