This article analyzes the participatory design of the Portal e‐Democracia, sponsored by the Brazilian Chamber of Deputies. More specifically, it examines how citizens took part in the online discussions about the Brazilian laws on the Budget Guidelines, the 2013 Annual Budgeting, and the Political Reform debates of 2013 and 2015. We hypothesize that discussion forums with identical structures can nevertheless host debates with very diverse characteristics. The methodological approach considers a quantitative content analysis, using descriptive statistics and correspondence analysis to examine how the forums’ features were related to their structure, in terms of user identification, openness and freedom of speech, agenda, and moderation. We also examine the quality of public debate in these arenas by considering the interactions with regard behaviors of justification, reciprocity, and respect. We find that, even though the space for debating was structurally the same, every forum had some particular characteristics concerning the discussions. This leads us to consider the issue at stake and the sociopolitical context as variables that are more important for characterizing the debate than structure per se.