We describe a model and system to support collaboration in requirements analysis with hypermedia technologies. The hypermedia support approaches the issues in communication, agreement, and traceability management, which are critical in the early phase in requirements analysis. Our approach consists of (1) an extension of the Inquiry Cycle model, a cyclic model of requirements analysis, for the collaborative work, and (2) comprehensive interaction media that fully utilizes WWW (World Wide Web) and Internet technologies. In this paper, we review the lessons learnt from experiences in applying the Inquiry Cycle model and Tuiqiao, a hypertext tool based on the model, to collaborative work in requirements analysis of a telephone directory service. We then propose an extension of the model and discuss the design of EColabor, a networked hypermedia system for requirements analysis. EColabor is based on the extended Inquiry Cycle model and implemented with the web and Internet technologies, including distributed version control and audio/video conferencing.