OpenDoc is in fact the result of a colaboration of several companies. These companies (IBM, Apple, Novell, Wordperfect) formed the Component Integration Labs organization.
OpenDoc is built around SOM, a CORBA ORB by IBM. It is completely object oriented. OpenDoc intended to broke the concept of monolithic applications, you would be able to build your own applications from parts, with a little of scripting.
Currently IBM has abandoned OpenDoc. In one of their pages they say they will release it to the public domain. This would be immensely useful to the free software community, so if you can, write IBM reminding them of this promise: http://www.ibm.com/software/ad/opendoc/position.html
There are currently projects in both KDE and Gnome camps that promise to come up with a component model, however it will be seen if they will do all that OpenDoc already did (or they blindly are following the lead of OLE and COM).
If you want to learn more about this technology, you could visit http://www-4.ibm.com/software/ad/opendoc/library/ .