US Patent 7890848 Differential dynamic content delivery with alternative content presentation

Differential dynamic content delivery including providing a session document for a presentation, wherein the session document includes a session grammar and a session structured document; receiving a presentation control instruction to present a classified structural element of the session document, wherein the classified structural element comprises one or more versions of presentation content; determining whether at least one version of presentation content of the classified structural element exists for a user; identifying alternative display content for the user if no version of presentation content of the classified structural element exists for the user; and presenting the identified alternative display content to the user.