A method and system for transacting with an agency participating on an advertising exchange network for serving online advertisements. An advertising exchange agency may serve multiple roles in the advertising exchange network. The method includes storing a machine-readable representation of a plurality of network entities in a directed graph representation. Network configurations codified in directed graph representations include the identification of at least one agency that participates on the advertising exchange as well as identification of at least one network entity that does not participate on the advertising exchange, thus providing a buyer-seller online advertising marketplace. Servers are configured for transmitting an opportunity to serve an online advertisement to the advertising exchange network, and one or more network entities are configured to deliver the online advertisement. Financial transactions including revenue sharing payments to the agency are managed by traversing the network representation through one or more paths including the agency.