1. A method for differential dynamic content delivery, the method comprising: providing a session document for a presentation, wherein the session document includes a session grammar and a session structured document; providing a session copy of a user profile including a user classification, receiving, from a presenter, a user classification instruction to change a user classification in the session copy of a user profile; changing the user classification in the session copy of a user profile in dependence upon the presenter's instruction; selecting from the session structured document a classified structural element in dependence upon a user classification in the session copy of a user profile of a user in the presentation; and presenting the selected structural element to the user.