This study adapted the Unified Theory of Acceptance and Use of Technology (UTAUT) and innovation diffusion to show how virtual community building, website performance expectancy, effort expectancy, trialability, and two mediators (familiarity and perceived risk) interact and affect online shopping intention. A total of 430 valid participants were collected, all of whom had the goal of buying a smart phone. The results of the structural equation model analysis show that performance expectancy and effort expectancy positively affect website familiarity; virtual community building and trialability positively influence product familiarity; and perceived risk negatively affects purchase intention. In addition to the effects demonstrated by the regression results, website familiarity and product familiarity also have mediation effects. Finally, this study suggests that managers should provide a complete community to consumers in order to enable them to share information; furthermore, they should also provide details of product trials on the website, so that consumers can increase their familiarity with both the website and the products, as this can then raise consumer purchase intention.