This paper examines the social media use by diffuse and specific interest groups. An in-depth analysis of a random sample of tweets by diffuse and specific interests in the EU shows significant differences with respect to utilizing social media. Diffuse interests are not only more likely to use social media but they are also more likely to pursue two-way communication with their members and much more likely to mobilize them to take action than specific interests. Diffuse interests use the ‘@’ function more to directly reply to their members or other users, whereas specific interests use the ‘@’ function more to repost content from other users. We also found that the nature of tweets by these two types of groups differs. Diffuse interests are more likely to highlight issues which are of public interest like the rights of disabled people, jobs, youth, sustainability or saving a pub in a neighborhood. Specific interests’ tweets are more likely to be concerned with things like technology, innovation or transatlantic trade.
