In light of constructivism and cognitive psychology a networked learning system enabling students to construct multiple-choice questions, which can be assessed, viewed and answered by peers, was described in the paper. A preliminary study evaluating various functions and features in the system and its learning potentials was conducted with 52 six-graders. Overall, students rated favorably on the system's interface design and potentials in promoting their cognitive capability in the content domain. Student written responses combined with classrooms observations further provided descriptive evidence for the system facilitative effect for student learning. Via playing the roles of question posers, assessors, viewers, revisers and answers at different points in the learning process, students tended to actively engage in the learning process by constructing and re-constructing their own interpretations of the world of information around them, which is facilitative for their own understanding and cognitive development.