Customer relationship, commitment and retention are critical for e-commerce success. Existing IS research has studied e-commerce customers more from a system user perspective. We argue in this study that we should also take a customer perspective, which has significant research and practical implications in that it connects to business profitability directly. As our first attempt, this study, referring to both IS and marketing literature, examines how customer commitment and retention can be achieved to some degrees by high quality relationships with customers, which, from an information systems perspective, are influenced by the information, system and service qualities of e-commerce service providers (e.g., eBay.com). Using a sample of 140 online auction sellers at uBid.com, we empirically confirm that relationship quality is an important factor that mediates the impacts of IS factors (i.e., information, system and service qualities) on business profitability factors (i.e., customer commitment and retention).