A presentation server which enables a client device to run a network based application by sending structured data from one or more data sources to software on the client device. The presentation server decouples the client device from the data source by (i) insulating the data source from needing to handle directly any display, data storage, data querying or communications functions relating to the client device and (ii) insulating the client device from needing to handle communications functions which are specific to the data source.