Abstract: A document delivery system transmits a document file from a sender computer to a server computer. The server computer then stores the document file at a particular network address, sends a message to the receiver computer indicating the network address of the document file, and later forwards the document file to the receiver computer when the receiver computer requests the document file at that network address. Viewer software running on the receiver computer processes the received document file to produce a display of the document it describes after which the viewer software returns data to the server computer indicating that it successfully displayed the document. The server computer logs a record of the successful receipt and display of the document and makes that record accessible to the sender computer. If the viewer is unable to successfully display the document, it does not return the indicating data to the server.