Developing information integration systems today is largely done by hand, in a very labor intensive and error prone process. In this paper we describe MOBS, a conceptually new solution to this problem. MOBS employs mass collaboration. It asks the users of an information integration system to "pay" for using the system by answering simple questions, then uses those answers to further develop the system. This way an enormous burden of system development is lifted from the system builders and spread "thinly" over a multitude of users. We present both simulation and real-world experiments which suggest that MOBS can build systems accurately and efficiently. Finally we discuss the potential applications of MOBS beyond the information integration context.