With social networking and Web 2.0 technologies becoming increasingly popular, they pose great potentials and challenges for the future of E-commerce. Social shopping sites emerged as the latest developments to leverage the power of social networking with online shopping. Users on social shopping sites can post product recommendations, create wish lists, post photos, make purchases, and form social shopping communities. Despite enormous business interests and potentials, little is known about whether users will adopt such systems. This research-in-progress paper proposes to apply and extend the Technology Acceptance Model (TAM) to understand the adoption of social shopping sites, and the factors that lead to the adoption. TAM posits two factors, the perceived ease of use and the perceived usefulness, determine a person's intention to use a new IT. This study explores two additional antecedents in the context of social shopping adoption: an online shopper's tendency to social comparison, and trust in the website. The extended TAM model will be tested through surveys. This research is among the very first to systematically examine the merge of social networking with E-commerce technologies. With the increasing importance of Web 2.0 to E-commerce, this study is timely and important.