This article evaluates the potential that Twitter affords politicians to communicate to citizens directly, through messages that they broadcast to users who follow them, and indirectly, to the extent that their followers autonomously re-circulate politicians’ messages to their own contacts. Analysis of more than 2 million accounts of followers of 10 national party leaders during the Italian 2013 general election campaign shows that most users are rather inactive and have very small followings. Moreover, the most followed politicians have on average the least active and followed users, and vice versa. Users’ activity and followings are also unevenly distributed, with very tiny minorities accounting for the vast majority of tweets and followers. The most followed followers of politicians are celebrities in realms other than politics, or people who are already highly visible in the politics-media ecosystem. Our findings suggest that most of the potential for indirect communication may lie in the "vital middle" of the Twitter population who are more active than average, but are not part of the restricted elite of high-impact outliers.