This paper examines how the use of social media affects participation in offline demonstrations. Using individual web survey data from Norway, we ask whether social media usage serves to re-affirm or transcend socioeconomic divides in participation. In addition to data on demonstration participation in general, we also use the data on the Rose Marches that were organized after the 22/7 terror events as a critical case. Our results show that the type of participant mobilized via the social media is characterized by lower socioeconomic status and younger age than those mobilized via other channels. We also show that connections to information structures through social media exert a strong and independent effect on mobilization. Our findings thus appear to corroborate the mobilization thesis: social media represent an alternative structure alongside mainstream media and well-established political organizations and civil society that recruit in different ways and reach different segments of the population.