A user-centered approach in the development lifecycle of e- commerce websites is nowadays a crucial factor in the success of any on-line business. The purpose of this paper is twofold: a) to identify the factors that affect e-commerce website usability and b) to analyze the role of those factors in increasing the effectiveness of e-commerce web sites. Furthermore, it presents the application of a Multicriteria Satisfaction Analysis (MUSA) method to rank usability attributes in websites based on their competitiveness importance. A case study in eight e-tourism web-sites is presented as a demonstration of this work, the outcome of which will help usability specialists and e-commerce website developers to determine specific usability attributes that are more crucial to the overall usability and user satisfaction of a website. The results of the proposed approach suggest that for each e-commerce website certain usability attributes are likely to be more crucial to the success of the e-commerce website than others. Therefore, identifying the relevant usability attributes in advance through customers' feedback can be a great advantage to website developers if they want to have an edge over other competitors.
Keywords: Web usability, E-commerce, E-tourism, Multicriteria analysis, Customer satisfaction analysis
Electronic commerce refers to a wide range of online business activities for products and services . Electronic commerce reduces costs and extends existing distribution channels, extending existing business models. Web usability is one of the important factors that determine the success of e-commerce websites . A website which is not user friendly will drive users away . Moreover, others will also be advised to avoid it. It is difficult to convince dissatisfied visitors to revisit your website even if you launched a new site.
In e-business, the website is the firm's interface with the customer, and its usability is crucial to the success of the venture. E-business success is determined in part by trust , and research shows a strong relationship between website usability and trust.
In his book, Usability Engineering, Nielsen  defines usability in terms of a number of users' oriented attributes. According to Nielsen , usability refers to:
* The ease of learning how to use the interface
* The efficiency of the interface design
* The ease of memorizing how to use the interface
* The reduction of errors
* General satisfaction with the interface
Usability in ISO 9241-11 is defined as "The extent to which a product can be used by specified users to achieve specified goals with effectiveness (fit for purpose), efficiency (taking less time to achieve a particular task) and satisfaction in a specified context of use". According to Jakob Nielsen  usability is a quality attribute that assesses how easy user interfaces are to use. The word usability also refers to methods for improving the ease-ofuse during the design process.
Human-computer interaction (HCI) is the study of interaction between humans and computers . The objectives of human computer interaction design are to produce usable, secure and functional systems. People's concern has been of utmost importance in HCI, since they will use these systems in their everyday life. The usability and design of websites have received much attention in the human computer interaction (HCI) literature as well as in webspecific usability research. Usability and its determinants pose a considerable challenge to usability interaction designers and electronic commerce website developers.
The term user experience (most often abbreviated UX, but sometimes UE) refers to a concept that places the enduser at the focal point of design and development efforts, as opposed to the system, its applications or its aesthetic value alone. It's based on the general concept of user-centered design. …