Résumé : This dissertation endeavours to shed some light on the reasons behind the predominance of populist parties on social media in the EU member states, issue which has been scarcely explored by the existing research. It starts from the results of our prior analysis revealing that in 18 out of the 27 countries concerned populist parties have highest numbers of followers on Facebook, the main social platform in Europe. In this paper we analyse 260 Facebook posts from 13 official pages of Belgium’s political parties represented in the European Parliament, looking for elements of populist discourse. Subsequently we compare the numbers of shares by Facebook users of publications containing populist elements with numbers of shares of other posts. The results show that Facebook posts containing populist discourse are shared significantly more often than other ones. However, there seems to be a clear difference in virality between posts using strong populist language and those which contain some elements of populism but also offer solutions and tend to be constructive. Such ‘soft’ populist discourse does not seem to have incidence on the number of shares according to our analysis. These results could possibly be also seen as confirming the existing research pointing to the role of strong emotions as a vector of popularity on social media. Certainly, the significance of our results is limited by the number of Facebook posts analysed.