  With the irruption of ICTs and the crisis of political representation, many
online platforms have been developed with the aim of improving participatory
democratic processes. However, regarding platforms for online petitioning,
previous research has not found examples of how to effectively introduce
discussions, a crucial feature to promote deliberation. In this study we focus
on the case of Decidim Barcelona, the online participatory-democracy platform
launched by the City Council of Barcelona in which proposals can be discussed
with an interface that combines threaded discussions and comment alignment with
the proposal. This innovative approach allows to examine whether neutral,
positive or negative comments are more likely to generate discussion cascades.
The results reveal that, with this interface, comments marked as negatively
aligned with the proposal were more likely to engage users in online
discussions and, therefore, helped to promote deliberative decision making.
