[영문]Recent policy efforts to encourage the use of health information technology are emphasizing development of communitywide health information exchanges to share clinical data across patient care settings. Interviews in twelve U.S. communities show that most large hospitals have or are developing physician portals to provide admitting physicians with remote access to patient records, but there is little data sharing among unaffiliated organizations. Competition among hospitals for physicians is a key factor driving adoption of these proprietary systems. In contrast, provider and health plan competition and adversarial relationships between providers and plans are viewed as major barriers to communitywide clinical data sharing.