Marc Canter's response to my post on true multimedia documents:

Lucas Gonze is blogging about a new medium - of true multimedia documents. We used to call those things 'compund documents'.

I think that these new things are different from compound documents in the sense that the underlying medium which the technology will have to support hasn't reached its final form yet. Whether they act more like record albums, plain old MP3s, or something completely new, they'll have a set of application-defined functionality which goes beyond what a generic format like a compound document can do.

I don't mean to say that the generic technology isn't critical, but that the social practices it is intended to support have to come first. RSS came after blogging, for example.