Recent studies have shown that online participation is a multi-dimensional phenomenon that replicates and extends existing forms of political engagement. What is less clear is the mobilizing potential of these different types of activity and particularly whether they trigger offline participation. This paper addresses these questions in an analysis of citizens online and offline behaviour in the context of a UK General Election. Specifically we identify three different modes of online engagement in the campaign, profile the individuals most likely to engage in them, and examine whether they affected individuals’ likelihood of voting. Our findings show that while newer social media based ‘e-expressive’ activities are most likely to appeal to those individuals who are not already engaged in politics they do not necessarily increase the likelihood of voting. By contrast higher consumption of news and information online during an election does appear to significantly boost individuals’ chances of turning out to vote.