Online social interactions are known to be useful to improve business performances. As l ocal business retailers have limited resources in marketing, they can benefit by using onli ne social interactions for their business performances. In the same line of purpose, the ret ailers also exploit an online platform, such as discount coupon sites: they sell online coup ons for their offline products and services in the platform. Notably, the online platform ca n play an important role in generating online social interactions as well as final sales arou nd the retailing brands. It also provides a distinctive setting for consumers in that they pur chase products and services online only to consume their use offline. Given that consume rs are motivated by different purposes, their online social interactions may differ in the di sparity of purchasing online and consuming offline. Previous studies have witnessed the r elationship between social interactions and sales, but the relationship between environme ntal influences and social interactions remains unexplored. In this paper, we focus on the influences of online and offline environments where consumers are situated with the online platform on generating online social interactions as well as final sales. To this end, we look into two types of social interactions, i.e., product discussion and social referral, and two distinctive environmental influences, i.e., the influences from the same product page and from the local retail revenue where the focal business is located. Using data on online social interactions and offline retail revenues around a major coupon site in South Korea, our empirical analysis demonstrates interesting findings. The two types of social interactions and final sales respond in different way to the environmental influences. To be specific, in the online purchase context, the absolute influence lowers the generation of product discussion and sales while promoting social referrals. In the offline consumption context, however, the proportionate influence plays a role in driving these three outcomes. Our findings suggest that local business retailers should deploy their online platform strategies by concerning online and offline environments, in accordance with the specific marketing objectives regarding social interactions and sales.