This study argues that students learn from each other, and contributing knowledge can improve their academic achievement. We developed the OpenSlide system, a teaching technology that combines the social function of SlideShare and YouTube, as an after-school, auxiliary learning tool. This study also used the stochastic actor-based model to model the face-to-face relationships and interactions of students recorded on the OpenSlide database system, and investigate any social influence on their selection of knowledge giving relationships. Our findings demonstrate that students' knowledge contribution network is affected by online interactions through OpenSlide. It also verifies that useful network structures can facilitate network evolution and knowledge construction across class boundaries, and improve students' academic achievement.