Mapping Exposure Diversity: The Divergent Effects of Algorithmic Curation on News Consumption.

Diversity is a crucial precondition for a democratic public discourse. In today's high-choice media environments, exposure to diverse news is largely determined by individuals' personal selection. Yet these decisions are increasingly shaped by online platforms, whose curation mechanisms may serve to expand or contract the diversity of encountered content. In a major extension of existing research, we show that positive short-term effects of platforms mask detrimental long-term effects. Drawing on a four-month tracking dataset and a comprehensive content analysis covering the online news consumption of over 10,000 German citizens, we demonstrate that even though short-term usage of platforms uniformly increases exposure diversity, long-term reliance can lead to decreases. In addition, platforms vary in their influences: News aggregators are beneficial to exposure diversity, while Twitter and search engines have a limiting effect; Facebook offers no significant influence. [ABSTRACT FROM AUTHOR]