This exploratory study with a small, non-representational sample attempts to explain the possible interplay between traditional Internet and social media and their combined influence on young voters’ everyday, face-to-face political discussion. Assumed and tested herein was that close-tie social media use would moderate the positive influence of exposure to heterogeneous opinions on the Internet on college students’ participation in offline political discussion due to the cocooning effect inspired by circular affirmation in close networks. From hierarchical regression analyses of a sample of 123 Korean university students, results supported the negative moderation of close-tie social media use. Lighter close-tie social media users were more likely to participate in offline political discussion as a result of heterogeneous exposure than heavier close-tie social media users. In addition, close-tie social media use facilitated higher political discussion for students with lower heterogeneous exposure. In discussion, however, it was cautioned that the increased political discussion due to higher close-tie social media use may not transfer to higher perspective-taking ability and political tolerance. Implications were provided for future research.