Democratic theorists often envision public deliberation as being essential to the working of democracy. Several scholars have also highlighted a potential for realising such deliberations on the internet. Consequentially, an emerging array of experiments in online deliberation has now been developed to achieve online discussions, which would be beneficial for democracy. However, few studies have yet attempted to compare the outcomes of online mini-publics to online citizens’ discussions in general. This article, thus, concerns an online experiment carried out in 2013 with the purpose of examining whether, and under which conditions, forums designed according to deliberative principles produce better ‘democratic outcomes’ – such as coherence of opinions, increased efficacy, trust, and propensity for civic participation – than online citizens’ discussions, which are ‘left to their own devices’. The study applies a post-test only, 2×2 factorial design, with a control group. In total, N=70 participants taking part in the experiment. The findings indicate that the effects of designing for deliberation were generally positive, albeit not for all of the democratic outcomes. In addition, methodological issues of relevance for the internal and external validity of the current experiment, which could be of relevance for future studies, are also brought forth.