U-commerce extends traditional commerce (geographic, electronic, and mobile) to a world of ubiquitous networks and universal devices, a world in which users can access networks at any time from any place, using a range of devices to invoke unique and personalized services. As such, u-commerce presents a new perspective on time and space. Specifically, four constructs are discussed that form the fundamental dimensions of u- commerce: ubiquity, uniqueness, universality, and unison. This report presents an experimental investigation to examine how two of these u-constructs, namely ubiquity and uniqueness, impact individual task performance, perceptions of usefulness and ease of use across differing levels of u-commerce technology and a variety of tasks. A total of 117 senior level MIS students served as subjects using the latest currently available form of u-technology: wireless personal digital assistants (PDA).