Online publishing, social networks, and web search have dramatically lowered the costs of
producing, distributing, and discovering news articles. Some scholars argue that such
technological changes increase exposure to diverse perspectives, while others worry that
they increase ideological segregation. We address the issue by examining web-browsing
histories for 50,000 US-located users who regularly read online news. We find that social
networks and search engines are associated with an increase in the mean ideological …