This article explores the relationship between different political uses for social networks and off-line political participation as well as the differentiated political-mobilizing effect of the Facebook, Twitter and WhatsApp platforms in a context of presidential elections in Ecuador. The results confirm that: (i) social networks stimulate popular mobilization involving offline political behavior; (ii) this mobilizing effect is limited to Facebook and WhatsApp platforms; and (iii) political uses of an expressive nature and contact with political groups have a stronger influence on offline political participation. The implications of these findings are discussed within the framework of the debate on the mobilizing effect of social networks on the degree of offline political activism.