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; identifying a recording period within a presentation session; recording, during the recording period, a presentation control instruction; selecting from the session structured document a classified structural element in dependence upon the recorded presentation control instruction and in dependence upon user classifications of a user participant in the presentation; and presenting the selected structural element to the user.