Proliferating Web-user interface studies prompt a need for theoretical approaches. This study presents a two-factor model that can guide Website design and evaluation. According to the model, there are two types of Website design factors: hygiene and motivator. Hygiene factors are those whose presence make a Website functional and serviceable, and whose absence causes user dissatisfaction (thus dissatisfiers). Motivator factors, on the other hand, are those that add value to the Website by contributing to user satisfaction (thus satisfiers). An empirical study is conducted in two phases. In Phase I, 44 core features and 12 categories of features were identified by a total of 76 subjects as Web design factors. In Phase II, 79 different subjects distinguished hygiene and motivator factors in the context of a particular Website (CNN.com). The results showed that the two-factor model provides a means for Web-user interface studies. In addition, Subjects in Phase II commented that, as time passes or familiarity increases with certain design factors, their identification of what are hygiene and motivator factors might change, promoting further investigation and possible expansion of the model. Suggestions for Website designs and evaluation, and further research directions are provided.