Dynamic addressing in transient networks

Methods, systems, and computer program products are disclosed for, in one aspect, persisting identifiers and relationships in a transient peer-to-peer networking environment where communities have ad hoc participants. Persistent identifiers are defined for nodes, allowing nodes to be identified across sessions and invocations, even though they re-enter the network with a different network address. Paths taken by content resources as they traverse the network (e.g. which nodes forwarded the content) are persisted, along with reputation information about nodes (e.g. indicating how successful they are at answering queries from peers). Trust relationships can be derived using the persisted information. A tiered broadcast strategy is defined for reducing the number of messages exchanged. Other aspects are also disclosed.