Differential dynamic content delivery including providing a session document for a presentation including a session grammar and a session structured document, the session structured document including a classified structural element for a first user who will not attend a presentation and a classified structural element for a second user who will attend the presentation; receiving, during the presentation, presentation control instructions controlling the presentation; selecting during the presentation classified structural elements for the second user in dependence upon the presentation control instructions and user classifications of the second user; presenting to the second user during the presentation the selected classified structural elements for the second user; selecting, after the presentation, classified structural elements for the first user in dependence upon the recorded presentation control instructions and the user classifications of the first user; and presenting after the presentation the classified structural elements selected for the first user.