In this paper, we introduce a novel way to utilize S3D in mobile UI design, and present the interaction design space where the depth visualization is used to distinguish between a shared and private information layer. This principle is used for content sharing in a mobile photo sharing application, see Figure 1. We present a mobile photo sharing application design, developed based on an iterative, user centric design process, a functional prototype, and the evaluation of the final design with a method adapted from the product reaction cards method [4].