It seems to me that a Pedagogical Interface (PI) will prove to be a primary outcome of online publishing. Since the 1990s, publishers have gotten very good at using the internet as an infinite library of digits, a gigantic distribution pipe with a cash register at every possible outlet, an immediate means to access everyone on the globe through computers, pdas, phones, etc., delivering digitized content, new and repurposed. But so what, if all we are doing is republishing articles and pictures (PDFs) of static books (ebooks), and sharing self-contained recordings?
The online medium allows for dynamic, recorded interaction and change between perceiver and perceived, and thus I think that it is in the arena of music where a PI might best be developed, an infrastructure for learning about “content” while experiencing it. Bob Stein and the Voyager group was responsible for an early incarnation of the PI in the 1990s with their Schubert Trout Quintet. This CD application for the Mac was in effect living, breathing liner notes, accompanying the musical performance of this exquisite music. They also produced a Beethoven CD, an archive copy of which can be found at http://www.futureofthebook.org/blog/archives/2009/11/published_by_the_voyager_compa.html
Music is universal (no need of translation), experiential, transcendent; our familiar media of paper (books, sheet music, liner notes, articles) is arguably the wrong medium for the musical message. Developing the PI in this area could bring us listeners, learners, performers to a vibrant new terra incognita. Maybe.