XPORT is a profile-driven distributed data dissemination system that supports an extensible set of data types, profiles types, and optimization metrics. XPORT efficiently implements a generic treebased overlay network, which can be customized per application using a small number of methods that encapsulate application-specific data filtering, profile aggregation, and optimization logic. The clean separation between the "plumbing" and "application" enables XPORT to uniformly and easily support disparate dissemination applications. We demonstrate the basic XPORT system, featuring its extensible optimization framework that facilitates easy specification of a wide range of commonly used performance goals. We demonstrate iterative tree transformation protocols that allow XPORT to continuously optimize its operation to achieve these goals under changing network and application conditions. We will use two different underlying applications, an RSS feed dissemination applic...