Questions are an important trigger of learning as well as social interaction, and question asking is a common technique that teachers and practitioners use in classrooms for motivating and engaging students. In the context of online video-based learning such as MOOCs, however, there remains limited understanding around whether questions benefit online learning and how to systematically use questions to support learners online. In this paper, we present a questionization technique which can transform comment left by previous learners into question forms to display to new learners. Through a user study, we investigate how such transformation of peer comments influence learning experiences. The results indicated that showing high proportion of questions along with a control of the total amount of information displayed can positively impact learning experience and participation.