As customers gain Web site-specific skills they come to perceive the Web site differently and more favourably than inexperienced customers. This is not only due to familiarity, emotional attachment, liking, trust, etc. Often, it is the result of an objective change in the utility of the interface as a result of skill acquisition. This chapter reviews recent work on the link between skill acquisition and loyalty in electronic environments, and extends this work by investigating the impact that learning has on consumers’ perceptions of electronic interfaces. I report the results of an experiment, which demonstrates that with increasing task experience the probability that participants will choose an incumbent Web site, over an objectively equivalent competitor, increases. In addition the data indicate that with increasing experience participants’ perceptions of product quality also increase. Although the two interfaces (i.e., incumbent and competitor) are not perceived to be any different when each has been used only one time, there is a significant difference in quality perceptions between the interfaces when the incumbent has been used six times and the competitor has only been used once. These findings are important, because perceptions of quality have an impact on the choices that customers make when shopping online. Therefore, changes in perception that occur with increasing exposure to the incumbent are meaningful and can have an impact on a Web site’s market share. The data presented in this chapter provide strong evidence that perceptions of interface quality are affected by experience with an interface in a way that gives an incumbent an advantage over competitors.