To succeed in the highly competitive e-commerce environment, it is vital to understand the impact of website quality in enhancing customer conversion and retention. Although numerous contingent website attributes have been identified in the extant website quality studies, there is no unified framework to classify these attributes and no comparison done between customer conversion and retention according to the different website quality attributes and their varying impact. This study adopts the model of Information Systems (IS) success by DeLone and McLean to provide a parsimonious and unified view of website quality, and compares the impact of website quality on intention of initial purchase with that on intention of continued purchase. With the proposed framework, we seek to understand how a company can increase customer conversion and/or retention. Our findings demonstrate the strength of our framework in explaining the impact of website quality on intention to purchase on the Web, and that website quality constructs exert different impact on intention of initial purchase and intention of continued purchase. The results suggest that an online company should focus on system quality to increase customer conversion, and on service quality for customer retention.