  Decide Madrid is the civic technology of Madrid City Council which allows
users to create and support online petitions. Despite the initial success, the
platform is encountering problems with the growth of petition signing because
petitions are far from the minimum number of supporting votes they must gather.
Previous analyses have suggested that this problem is produced by the
interface: a paginated list of petitions which applies a non-optimal ranking
algorithm. For this reason, we present an interactive system for the discovery
of topics and petitions. This approach leads us to reflect on the usefulness of
data visualization techniques to address relevant societal challenges.
