David Gelernter, a professor at Yale:
Mr. Gelernter believes streams are a more intuitive, useful way to organize our digital lives, not least because, as the past and future run off either side of our screen, at the center is now—and now is what the Internet really is about … Users will become comfortably accustomed to tracking and manipulating their digital objects as streams rather than as files in a file system. The stream will become a mirror of the unfolding story of their lives.
This actually sounds like how the Apple view of the file system works today: you have different versions of a document embedded in one file, which you can access and manipulate using Time Machine or the equivalent.