1. A system for displaying a document to a user, the system comprising: a profile bank storing a user profile including medical information about said user; a substitute document server storing personalized content comprising health-related information; a user set configured to display documents; and a controller configured (a) to retrieve original content in a document from an original content provider, (b) to retrieve with the user profile, and (c) to generate a modified version of the document by replacing at least a first portion of the original content in the document with a second portion of the personalized content received from the substitute document server based upon the medical information about the user, wherein the first portion of the original content in the document is modified using the second portion of the personalized content to generate the modified version of the document prior to display of the modified version of the document to the user via the user set, wherein the first portion of the original content in the document that is replaced is selected based upon an identifier in the original content.