Despite the impressive democratic gains of the Indonesian political system since the fall of the authoritarian New Order regime, a noted weakness of the current political party system is the lack of clear ideological positions across parties and the difficulty that voters face in differentiating policy programs in order to hold parties accountable. Yet, with the increasing popularity of social media, new channels of communication are opening up between political parties and their constituents, reshaping Indonesia’s political communication landscape. This raises the question of whether these new forms of media offer spaces that allow, or even encourage, parties to articulate ideological positions and discuss issues of public concern with constituents. This paper addresses this question through a mixed-methods analysis of how political parties are using the popular social media website Twitter and how users are responding to party messaging strategies. Based on a content analysis of party messages, qualitative observation of party-constituent interactions, and a quantitative analysis of user response, the findings suggest that there is reason for modest optimism that the medium of Twitter encourages a less superficial brand of party communication. Whereas other studies have found that the goals or the size of the party as the best explanation for the social media strategy and performance, the Indonesian case suggests that parties that attempt to differentiate themselves ideologically, regardless of their ideological content, and engage the public directly perform better on Twitter. It also finds that tweets about electoral politics receive the most reaction from users. This suggests that Twitter is a medium that will reward more programmatic and engaged party messaging, with potentially positive impacts on the Indonesian political communications landscape.