Relative advantage and perceived usefulness are often used interchangeably in the literature. We argue that this limits the understanding of the adoption of ICTs, especially when there are multiple alternatives. To address this issue, we reexamine relative advantage in relation to perceived usefulness by illustrating the conceptual differences between these two constructs, providing a re-specification of relative advantage stressing explicit comparison between ICTs, and then empirically testing a model that explores the roles of these constructs in explaining and predicting the adoption of a new technology in the presence of an existing ICT. The results demonstrate that perceived usefulness and relative advantage are indeed related but distinct constructs - relative advantage is a function of the perceived usefulness of new and existing technologies. While the perceived usefulness of a technology does explain the adoption of it to some extent, its relative advantage allows us to incorporate the influence of other technologies that would be otherwise ignored.