An increasing number of technologies and applications have begun to focus on mobile computing and the wireless Web as a way to conduct commerce-oriented transactions. M-commerce Websites that are usability friendly must emphasize information quality, system quality, and service quality, as these are proxy measures to mobile commerce user satisfaction (MCUS). Measureable variables can help researchers to understand how satisfaction induces users to return to a Website. Although several studies on m-commerce user satisfaction focus on content quality, appearance, service quality, and ease of use, the results of these studies were inconclusive because they do not address contextual usability barriers for the mobile Web. The task context, which consist of two activities, search and transaction, is a prominent contextual factor that affects mobile usability positively or negatively in achieving MCUS. The researcher determined what end user expectations and actual usage beliefs result in disconfirmation or MCUS. An empirical field study of an online retailer and search platform was conducted using a sampling of 98 participants. The participants used a smartphone to search and complete a transaction in the participant's natural setting. The study results indicated that expectations and usability measures including efficiency, errors, and flexibility significantly influence actual usage leading to MCUS. The original Expectation Confirmation Theory (ECT) model assumed that user's expectations could lead to actual usage. However, in the modified ECT model, it is the actual usage experience itself that determines MCUS. Disconfirmation is an inconsistent measure tied to actual usage, purchase intent, or satisfaction as mobile users often make purchases from m-commerce Websites because of convenience, flexibility, efficiency, and accessibility. If the user experiences an error during the search or transaction activity, such a drawback can cost a mobile Website future traffic, the loss of a transaction, and lead to lower levels of satisfaction. [The dissertation citations contained here are published with the permission of ProQuest LLC. Further reproduction is prohibited without permission. Copies of dissertations may be obtained by Telephone (800) 1-800-521-0600. Web page: http://www.proquest.com/en-US/products/dissertations/individuals.shtml.]