The purpose of this study is to define whether the generation of product-related information on the Internet, which explains the degree of consumer interest in the product, will cause a change in the diffusion pattern by the clarify the characteristics of diffusion by media to event of product launch. It is also to understand interest about product. This paper targets product launched at similar times in the three major brands in the Korean smartphone market, which is Apple's iPhone, Samsung's Galaxy, and LG's Optimus. The analysis data is the information on online news and blog from the time of occurrence of the product-related information until four years later. Bass Diffusion Model and J-test are performed to verify information diffusion pattern, and t-test is performed to verify hypothesis. We find the result what product information was relatively many generated at the time of product launch, so the innovation effect was high and the imitation effect was low. The pattern of diffusion occurred prior to product release did not be change by product release. This means that it is possible to know the diffusion pattern of product-related information, which is the degree of customer's interest, before product launch. Also, News that provides objective facts is higher imitation effect than blogs that focus on opinion leaders. Therefore, companies will be able to use these results to grasp the type of information-related information diffusion prior to product launch, to grasp the level of customer interest, and to perform strategic activities such as promotion activities.