Abstract: For a multi-party advertising exchange including advertising and publishing entities from different advertising networks, the invention provides architectures for an online advertising marketplace that range from lightweight to heavyweight implementations. A lightweight client side implementation of an interface includes centralized processing and storage of federated advertising marketplace data by centralized servers or services. A heavyweight client side implementation of an interface for advertising entities includes providing a peer instance of a federated advertising exchange application or set of processes is provided to each advertising entity as an interface for advertising entities where processing and storage are performed locally to each peer instance. Distributed advertising data can be replicated or synchronized with other peer instances.