This thesis presents the design and evaluation of content-based publish/subscribe systems for efficient content dissemination and sharing of dynamic and large-scale networked applications. The rapid development of network technologies and the continuous investment in network infrastructure have realized a ubiquitous platform for sharing information. However, there lacks efficient protocol and software that can utilize such resource to support novel networked applications. In this thesis, we explore the possibility of content-based publish/subscribe as an efficient communication substrate for dynamic and large-scale networked applications. Although content-based publish/subscribe has been used extensively in many small-to-medium scale systems, there is no Internet-scale applications that utilize this technology. The research reported in this thesis investigates the technical challenges and their solutions of applying content-based publish/subscribe in various applications in mobile networks and Internet. We apply content-based publish/subscribe in the interest-driven information sharing for smartphone networks. We design efficient approximate content matching algorithms and data structures. We study how to construct optimal overlay publish/subscribe overlay networks. We propose architecture designs that make Internet content-based publish/subscribe robust. We also design a name resolution system that enables content discovery in the Internet. These techniques are evaluated comprehensively in realistic simulation studies, and some of them are further evaluated on PlanetLab testbed with prototype implementations. / Computer and Information Science