We investigate the impact of the diffusion of high-speed Internet on different forms of political participation, using data from Italy. We exploit differences in the availability of ADSL broadband technology across municipalities, using the exogenous variation induced by the fact that the cost of providing ADSL-based Internet services in a given municipality depends on its relative position in the pre-existing voice telecommunications infrastructure. We first show that broadband Internet had a substantial negative effect on turnout in parliamentary elections between 1996 and 2008. However, we also find that it was positively associated with other forms of political participation, both online and offline: the emergence of local online grassroots protest movements, and turnout in national referenda (largely opposed by mainstream parties). We then show that the negative effect of Internet on turnout in parliamentary elections is essentially reversed after 2008, when the local grassroots movements coalesce into the Five-Star Movement (M5S) electoral list. Our findings are consistent with the view that: 1) The effect of Internet availability on political participation changes across different forms of engagement; 2) It also changes over time, as new political actors emerge who can take advantage of the new technology to tap into the existence of a disenchanted or demobilized contingent of voters; and 3) These new forms of mobilization eventually feed back into the mainstream electoral process, converting “exit” back into “voice”.

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