  The rise in popularity of Twitter has led to a debate on its impact on public
opinions. The optimists foresee an increase in online participation and
democratization due to social media's personal and interactive nature.
Cyber-pessimists, on the other hand, explain how social media can lead to
selective exposure and can be used as a disguise for those in power to
disseminate biased information. To investigate this debate empirically, we
evaluate Twitter as a public sphere using four metrics: equality, diversity,
reciprocity and quality. Using these measurements, we analyze the communication
patterns between individuals of different hierarchical levels and ideologies.
We do this within the context of three diverse conflicts: Israel-Palestine, US
Democrats-Republicans, and FC Barcelona-Real Madrid. In all cases, we collect
data around a central pair of Twitter accounts representing the two main
parties. Our results show in a quantitative manner that Twitter is not an ideal
public sphere for democratic conversations and that hierarchical effects are
part of the reason why it is not.
