Open data initiatives are critical to open government policies which promote transparency, citizen engagement and collaboration. However, they face challenges in realizing their potential benefits through citizens' active engagement. Despite the sharp rise of social media use by governments or quasi-governmental organizations to engage citizens in transforming public service quality and offers, very little has been written on enabling roles of social media in influencing the outcome of open data initiatives. This research examines the potential enabling roles of social media in motivating and having citizens' engagement easier in open data environments. Specifically, we present social media use in supporting citizen-sourcing initiatives in response to an open data initiative. We examined the 2014 Indonesian presidential voting results by the Indonesia General Election Commission as the case study context. Our study proposes two complementary roles of social media in enabling the realization of the benefits from opening election voting results transparent.