User perceptions toward information technology (IT) are crucial to its successful implementation. The purpose of our study is to improve the understanding of the impact of social influences on different types of users' perceptions and adoption of IT. To do this, the study refines and expands the operationalization of the social influence construct to include four components: subjective norm, image, visibility, and voluntariness. This is used to examine influences by type of user (knowledge worker versus university student) and IT (innovative versus mature). The key finding is that when knowledge workers consider adopting innovative IT they are sensitive to general perceptions of its usefulness. The results have implications for management enquiry and practice.