The diffusion process of mobile application has several distinctive features. First, unlike other products, there is little cost to acquire and abandon mobile applications. This easy-come-easy-go makes the issue of assimilation gap most prevalent in the mobile application diffusion. Second, many applications are tested on a popular platform before the market introduction or promoted from already popular applications, which can form the early market and accelerate the diffusion of such applications. This self-referencing can make the unique diffusion pattern, particularly in the early stage of the market introduction. Lastly, the diffusion process of applications, especially for those in the same category, can be interrelated with each other. This within-category dependency might require the diffusion of applications in the same category to be modeled together. We develop and empirically validate a flexible diffusion model to accommodate aforementioned distinctive features in the diffusion process of mobile applications.