1. An extensible document processing arrangement comprising: one or more document service cards each indicating one or more document services; a document processing platform for creating a document output from a document input stream, said document processing platform comprising: one or more slots, each of said one or more slots for receiving a document service card; service registration means for marking document services as available in a service taxonomy responsive to detection of a document service card being received by one of said one or more slots; service deregistration means for marking document services as unavailable in said service taxonomy; input means for receiving a document input stream representing a document to be processed and control forms; means for detecting and extracting control forms contained in said input stream; a service dispatcher for receiving an instance of a control form and selecting a document service in said service taxonomy to process said instance of said control form; and output generation means for reproducing said document input stream responsive to said selected document service.