1. A non-transitory, machine readable storage manufacture having stored thereon computer program code for execution by a processor, the computer program code comprising: a graphical editor for building an expert system; and a player component configured to execute the expert system; the graphical editor comprising a page editor component configured to interactively build page entities of the expert system, wherein exactly one of the page entities is identified as a start page to be displayed when execution of the expert system is commenced, each page entity consisting of: one or more content sections and one or more interface sections, wherein each content section of the page entity is constrained to consist of non-interactive static blocks of informational content for display, without any executable elements or interactive elements, and each interface section comprising: at least one widget to acquire input data via a user interface device coupled to the processor, and at least one interface result entity, the interface result entity identifying at least one of (a) a destination page, and (b) one or more result conditions; and further identifying one or more specified actions which are to be performed only if the result conditions are true; the player component arranged to access the start page entity, display the content section of the start page entity, acquire the input data from the user interface device, based on the input data, update zero or more stored variables of the expert system; and then, access the interface result entity of the start page, test the result conditions based on current values of the stored variables, determine whether the result conditions are true, and if the result conditions are true, executing the actions specified in the interface result entity; if the interface result entity of the start page specifies a destination page entity, navigate to the destination page entity, display the content section of the destination page entity, acquire second input data from the user interface device, based on the second input data, update zero or more stored variables of the expert system; and repeat the steps of executing one page entity at a time of the expert system, navigating from each currently displayed page to a selected destination page as determined by analyzing the interface result entity of the currently displayed page; the graphical editor further including an export subsystem configured to convert the page entities into a portable format to export the expert system for use by an independently executable player system, wherein exported expert system is self-contained, meaning capable of execution without specialized tools, plugins, external programs or access to a knowledge base, as the subject matter expert knowledge for the expert system is captured and reflected in the page entities.