Danai and the Microsoft researchers Paul Bennett and Eric Horvitz studied information-seeking behavior and access to alternative versus reinforcing viewpoints for strongly polarizing topics.

In particular, they analyzed the search and browsing behavior on the gun control debate following a shocking news event, the Sandy Hook Elementary School shootings in Newtown, Connecticut.

The paper is at: http://arxiv.org/pdf/1405.1486v1.pdf
The MIT Tech Review article is at: http://www.technologyreview.com/view/527311/sandy-hook-the-gun-control-debate-and-the-insidious-influence-of-the-filter-bubble/
Other press coverage includes: http://www.technology.org/2014/05/13/ideological-internet-bubbles-stay-strong-study-shows/#