In this paper, we focus on the "Question-Answer" function of SOUTO ; a hypermedia authoring system, and classroom activities where learners make hypermedia compositions with SOUTO and discuss their compositions with the function mentioned above. Field tests of the system reveal that ; 1 . The Question-Answer function reconfigures social relationships in the classroom and thus creates a foundation for collaborative learning, 2 . The Question-Answer function creates a field of informal talk, 3 . The SOUTO system provides a foundation on which both formal and informal talks are constituted and woven together, and thus, enables transition between them. Based on these findings, we suggest that educational systems should be designed as mediators which hybridize school-like activities and non-school-like activities.