  Among the topics discussed on social media, some spark more heated debate
than others. For example, experience suggests that major political events, such
as a vote for healthcare law in the US, would spark more debate between
opposing sides than other events, such as a concert of a popular music band.
Exploring the topics of discussion on Twitter and understanding which ones are
controversial is extremely useful for a variety of purposes, such as for
journalists to understand what issues divide the public, or for social
scientists to understand how controversy is manifested in social interactions.
  The system we present processes the daily trending topics discussed on the
platform, and assigns to each topic a controversy score, which is computed
based on the interactions among Twitter users, and a visualization of these
interactions, which provides an intuitive visual cue regarding the controversy
of the topic. The system also allows users to explore the messages (tweets)
associated with each topic, and sort and explore the topics by different
criteria (e.g., by controversy score, time, or related keywords).
