Date of Award


Degree Type


Degree Name

Doctor of Philosophy (PhD)

Graduate Group


First Advisor

Sandra González-Bailón


This dissertation investigates how digital intermediaries shape news consumption. In particular, the study is designed to address how social media, search engines, news aggregators, and email are associated with information concentration, audience fragmentation, and news inequality. The analyses leverage a large panel tracking the web browsing behavior and demographic attributes (each month N ~ 100,000 panelists). This panel data is processed and analyzed to uncover temporal trends in news consumption and changes in co-exposure networks (on the aggregate), and to identify mechanisms of exposure to news (at the individual level). Methodologically, the analyses rely on data mining, large-scale text processing, network analysis tools, and fixed- and random-effects regression models

I find that digital intermediaries are associated with a lower level of information concentration; in other words, they help diversify the sources people consume. Direct traffic benefits a narrower set of outlets, compared to mediated traffic. This pattern suggests that mediating platforms are expanding, on average, the range of information sources people access online.

Regarding audience fragmentation, I find that digital intermediaries are associated with less fragmentation: they increase density in co-exposure networks and promote traffic from core to peripheral (or niche) outlets. At the individual level, digital intermediaries are also associated, on average, with more ideologically moderate news diets.

Finally, the analyses of news inequality reveal a paradox: on the one hand, digital intermediaries are associated with a reduction or even the reversion of many news gaps separating various demographic groups; on the other hand, they are also associated with a lower level of news engagement (measured in terms of number of pages visited and time spent consuming news). These opposing trends are likely to hinder the positive impact that news exposure can have on civic outcomes, such as an increase in political knowledge and engagement.

Overall, this dissertation uncovers the different pathways giving access to news on the web, and identifies who is more likely to benefit from that access, both from the supply side (news outlets) and the demand side (audiences). By focusing on digital intermediaries, this dissertation casts light on the relevance of online curation in shaping the information people consume.


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