We fully support the standards bodies position on the use of individual ISBNs to identify the various different manifestations of a work. If there are three different ebooks, a hardback, two different paperback an audio and a large print, then each should be identifiable.
We also have long supported the use of the standard work number which has taken what seems an age to come to the market but can still do a much needed job in grouping all the various manifestations of a work under one umbrella. It would be good if some major players were to now insist on it use and full adoption and force the market to use it. There is nothing more frustrating than finding the various manifestations more by accident or resolving a widget only to be made aware of one of the works manifestations. The ITSC is not a traded unit but an attribute, or descriptor, that enables you to group many individual traded units together for information. It could be adopted initially just to group the digital manifestations of a work.
The other interesting areas are the selling of chunks, part works, chapters of digital editions and time rentals. These are harder to resolve but are equally important as they may have to be identified against royalty tracking, rights licensing and usage and permissions.
Finally, should be the ISBN on the copyright page of an ebook reflect; the physical book, the individual ebook, the work number? Today the ebook is usually a straight copy of the physical one and therefore using that should be acceptable but as they evolve and start to differ then this may not be the case. As the copyright relates to a work maybe this is where we should use the standard work number?
We do not envy the hard and often thankless work done by the standards bodies. They now not only have to grapple with an explosion of issues but more importantly have to communicate these succinctly to market and achieve their adoption.