This study questions the hypothesis that Twitter has become a privileged space to study, measure, and even “predict” public opinion. According to several academic works, the significant presence of “opinion leaders” on the network explains its “predictive” character. To discuss this hypothesis, we created a panel of 1,228 individuals, and we followed their activity for four months. The main result is that the majority of the participants, although strongly endowed with cultural capital, talk about politics only very rarely: only a minority can be likened to “opinion leaders.”