This paper proposes PhotoChat, a system that facilitates communication among users who want to share experiences by enabling them to share photos and notes. PhotoChat is designed to be used as a digital camera and to run on mobile PCs with a camera module. PhotoChat users can comment on the shared photos with a pen interface. The data, i.e., photos and comments, are distributed among PhotoChat users in real time to enable them to learn others' interests and to chat easily. In this paper, we show an implementation of our PhotoChat system and interaction patterns among PhotoChat users observed during our experimental evaluations. Keywords Chat on photos, collaborative photo annotation, communication support system, experience sharing ACM Classification Keywords H5.3. Information interfaces and presentation (e.g., HCI): Group and Organization Interfaces