New generation data dissemination systems such as P2P- based Pub/Sub ones become more and more complex. Understanding how they dynamically organize their participants or how the results are disseminated is not easy. Even harder is comparing systems. Our FleDDi demonstrator enables a deeper understanding of their flexibility, in particular through a nice dynamic visualization of the organization building and data dissemination. The audience will be able to experience different scenarios: high variety of the queries issued, presence of very popular queries, arrival of a participant with high dissemination capacities and issuing queries of varying complexity. Comparison may be drawn between several systems ranging from Unicast and Multicast to more evolved solutions such as Delta or QTor.