You have tried all the useful SPARQL queries and you have discovered a lot of interesting facts about your DITA content. But this is not the end, it's the beginning.
By now, you know what a graph looks like and have some notions about querying it.
Imagine how it would be to connect other graphs to your DITA metadata graph, such as a product metadata graph, or a company division graph? What about a client graph? The same way you have exported your DITA metadata graph, you could export and connect more metadata from the silos and databases of your organization. You would then be able to query all that data as a single graph and get answers to questions such as:
You could automate the creation of data feeds and reports that would give you the pulse of your organization and help you to take decisions based on tangible facts.
If you are interested in connecting your DITA metadata graph to more data, you can email me at colin@maudry.com, and, together, we will study your requirements.