1. A system for facilitating information transfer between a host computer and a client computer via a server computer, comprising: a host computer comprising a memory within which a presentation space buffer storing computer display information is configured and a communications interface enabling information exchanges using data streams, including transmission of the presentation space buffer as a presentation space data stream; a client computer comprising a web browser application displaying a markup language document and forwarding user inputs; and a server computer topologically intermediate to the host computer and the client computer and comprising: a server application framework comprising a display control interfacing to the host computer via a communications medium over which data streams are exchanged, including the transmitted presentation space data stream, and a host extension converting the transmitted presentation space data stream into a markup language document having instructions that identify position information for a cursor on a Web page and for modifying the presentation space buffer in the host; and a web server application interfacing to the client computer via a network medium over which the markup language document is served and the forwarded user inputs received.