How about evolving schemas? Allow for users/developers to collaborate on improving the different data types. Even though a schema may have a fixed set of core

How about evolving schemas? Allow for users/developers to collaborate on improving the different data types. Even though a schema may have a fixed set of core attributes, there's no reason why some app couldn't extend that in any way it sees fit. This way, any "file" generated with this app would be readable by everybody else while at the same time include the application specific extensions. Once the extensions become used by a large enough number of apps, they can be rolled into the standard.