The spectacular development of the Web 2.0, particularly through online social networks, has awakened much interest in different areas. Marketing is one of them and businesses have decided to experiment with this new type of technology in support to their commercial activities. However, to take advantage of Web 2.0 tools and sites, it is necessary to distinguish their scope and possible applications from a business standpoint. This requires putting Web 2.0 in clear perspective with e-commerce, which is inherently linked to this purpose. In this article, we clarify Web 2.0 and present how it can be used for marketing. In particular, we discuss the role that online social networks may have in e-marketing, and in doing so how such networks might relate to e-commerce. In addition, recommendations for e-commerce researchers are presented based on the evidence obtained.