Recently at work there have been folks asking about supporting different devices. The answer is always, "it depends on the viewer." This always seems to be the question of the day. A document type reflects a content creator and content viewer. IBM mentioned they would be supporting the ODF format in Lotus in hopes of spreading the standard. In this case, they are pushing for consistent viewers. The DITA format is having trouble with adoption because the editors are not very usable. This case is a content creation issue. This all points to the fact that standards are always going to be tough in computing because the apparent ease at which things can be customized.
On the positive side of data interoperability is XML. When I was in school, I was told XML allowed language creation. A program could write in a language and give another program the schema and like magic, the two could talk like old friends using XML. The problem is schemas are a pain to mess with and there is a huge gap between "reading" and "understanding". This is especially true with complex XML such as OWL.
I think in the long run the real power in XML is the ability to transform it. Through XSLT and friends, someone can take any document and transform it to be useful in a system. Take a look at the TCP/IP stack and I would argue that the uses of general XML are moving toward this model. What this means is that many intermediary formats can help data to move around in the stack. A client program keeps its specialized XML format, but when it gets sent to another system, it is wrapped. The next system to touch it breaks it down to its intermediary format and sends it along to the next stage. At each stage the XML is transformed to its own format and in doing so, allows new information to be created or passed along.
The major difference between this model and the current use is that systems try to send XML back and forth without an intermediary. This is akin to placing tons of business login in the UI, with the UI being the interface the applications experience. To clean up the UI for applications, there can be toolkits that are used simply for translating XML to appropriate formats as needed. This is essentially what our application does/can do. When considering this within the context of goverment required XML formats and million dollar content management systems, it makes quite a bit of sense.