Sponsored search ads appear next to search results when people look for products and services on search engines. In recent years, they have become one of the most lucrative channels for marketing. However, solid research is lacking to study why and how this channel works. In this paper, we investigate the mechanism web searchers use when deciding to click on a sponsored search ad. More specifically, we explore aspects of ad features and user characteristics that will influence the web searchers’ perceptions on sponsored search ads and their click behaviors. Based on previous literature, we propose a unified research model using Prominence-Interpretation Theory and the Heuristic Systematic Model. Preliminary analysis shows significant relationships between ad features and user characteristics with user perceptions that provide insight on sponsored search ads for researchers and practitioners.