You don't need to take a red pill to get the answer to this question. OpenDoc was a cross-platform compound document architecture originally designed by Apple for the Macintosh and then morphed into a SOM using, Corba'ized, framework when IBM got into the picture. From the user-interface side, the key notion was the ability to build documents (applications) out of parts. The parts could communicate with each other and interact via scripting. Compound documents were also stored together but the storage was structured so that you could access the data stored by individual parts as well as the whole document.

The C2 Wiki has a pretty good description. Here's another one that helps show the vision.

The compound document metaphor is a perfect fit for microcontent (and other) applications. This is an old idea whose time has come (again). Unfortunately, there are so few people who remember what this was or how it worked, that it will be probably reinvented (and badly).