How many participants are really enough for usability studies?
The electronic information revolution and the use of computers as an essential part of everyday life are now more widespread than ever before, as the Internet is exploited for the speedy transfer of data and business. Hotel/hospitality websites are growing in use worldwide, and they present popular business channels on the Internet. However, they need to be continuously evaluated and monitored to measure their levels of efficiency, effectiveness and user satisfaction, ultimately to improve quality and profit. Also, users have become the most important factor impacting on the success of these websites; if they are produced and are then deemed not useful by the end-users; the result is a failed business. Thus, nobody can use them and the stakeholders cannot make money. To assess the success of hotel/hospitality sites; usability criteria should be considered to ensure that users can find their way quickly and easily to complete their tasks effectively. This paper aims to use user testing and the thinking aloud protocol to evaluate two interfaces of hotel/hospitality sites to examine how their usability problems significantly impede user performance. The results show that usability is the main factor affecting users' performance, and that it is the best attribute for measuring the extent to which hotel/hospitality sites meet the requirements of their users and marketing strategy. Also, this study emphasizes to the one important concept in marketing which is related to usability concept is to understand the online user behaviour to deliver effective online user experiences, consequently, to achieve good e-marketing strategy. Because in this study, a high percentage of users failed in completing their tasks to reserve rooms for their journey. Thus, stakeholders fail in achieving the most important goal of their e-marketing strategy.