  The advent of WWW changed the way we can produce and access information.
Recent studies showed that users tend to select information that is consistent
with their system of beliefs, forming polarized groups of like-minded people
around shared narratives where dissenting information is ignored. In this
environment, users cooperate to frame and reinforce their shared narrative
making any attempt at debunking inefficient. Such a configuration occurs even
in the consumption of news online, and considering that 63% of users access
news directly form social media, one hypothesis is that more polarization
allows for further spreading of misinformation. Along this path, we focus on
the polarization of users around news outlets on Facebook in different European
countries (Italy, France, Spain and Germany). First, we compare the pages'
posting behavior and the users' interacting patterns across countries and
observe different posting, liking and commenting rates. Second, we explore the
tendency of users to interact with different pages (i.e., selective exposure)
and the emergence of polarized communities generated around specific pages.
Then, we introduce a new metric -- i.e., polarization rank -- to measure
polarization of communities for each country. We find that Italy is the most
polarized country, followed by France, Germany and lastly Spain. Finally, we
present a variation of the Bounded Confidence Model to simulate the emergence
of these communities by considering the users' engagement and trust on the
news. Our findings suggest that trust in information broadcaster plays a
pivotal role against polarization of users online.
