Polis is a real-time system for gathering, analyzing and understanding what large groups of people think in their own words, enabled by advanced statistics and machine learning. Polis has been used all over the world by governments, academics, independent media and citizens, and is completely open source. On Polis, people can post a comment about a topic or policy being discussed. Other users cannot directly reply to these statements, which reduces the likelihood of trolling and abuse. Instead, they can click “agree,” “disagree” or “pass/unsure” on each comment. Using real-time machine learning, Polis analyses all the votes on the comments to produce an interactive map that groups like-minded participants together in relation to other, differently minded users. The map lays bare the gaps between various groups — as well as any areas of agreement. Ideally, this incentivises people to post comments that attract more supporters, creating a path toward consensus.