Retailers having an online selling facility, or considering doing so, would benefit from a better understanding of the factors that influence consumers’ willingness to purchase online. This understanding would help them to plan their Internet strategies better, to design Web sites more effectively, to select the assortment of goods more likely to sell online, and to convert mere browsers into actual buyers. In fact, despite the worldwide diffusion and ever-increasing use of the Internet, e-commerce remains a limited phenomenon compared with the sales figures of traditional retailing: while an ever-increasing number of people use the Internet for gathering information, comparatively few buy online (Citrin, Stern, Spangenberg, & Clark, 2003; Dall’Olmo-Riley & Scarpi, 2005). This article aims at providing Internet marketing academics and practitioners with an account of the drivers and barriers to e-commerce, identified from a state-of-the-art literature review. The review is structured around the two main factors that appear to influence behavior on the Internet: consumer and product characteristics. Researchers agree that, although product characteristics play a role in e-commerce, the effects of attitudes, risk perception, and expertise are dominant. Hence, we first consider consumer characteristics.