Political Homophily in a Large-Scale Online Communication Network

As communication increasingly occurs in online environments, it is important to know the structure of such conversations in social networks. Here, we investigate patterns of conversation in online forums concerning politics, as well as patterns of cross-ideological interactions in forums that are not expressly political. First, we demonstrate a method for measuring the latent ideological preferences of more than 690,000 individuals using patterns of political commenting. Using this measure, we find that communication between ideologically dissimilar individuals becomes more common in periods of increased engagement with politics, that political homophily decreases as more individuals contribute to a conversation, and that forums dedicated to nonpolitical topics exhibit substantially less homophily than political forums. Theoretical implications for political communication on online platforms are discussed.