"Does dit use RDF?"
The answer to this question is critical to understand about how DitaBase is different: if you want it to, then yes! The validators and converters are fully Turing complete, and not limited to Javascript either. If you can make a language interpreter in C/C++ (think Javascript V8), then you can use it with DitaBase. So whatever format you want, just rebuild it in (or port it to) dit schemas. Therefore, it isn't possible for DitaBase to not be compliant with something (at least, as far as I can think) because if someone thinks its important, they'll rebuild it in dit schemas.
The reason DitaBase will succeed where Linked Data failed is by making DitaBase something that people in their day jobs want to use too, because the tools are just so good. Right now, a company with a data problem is extremely incentivized to seek a solution that solves only their specific problem. Obviously, because it's cheaper. But end-to-end solutions usually are not compatible with things like Linked Data, which needs solutions to be more general.
If a company sees that the best solution to that problem is becoming compliant with DitaBase, then obviously they're going to do it. But surprise surprise, now they're compliant with Linked Data as well.
So the first term that comes to my mind is RDF. How does it relate to Dit? Schema.org uses it, does Dit?
The problem I think it might be supposed to solve: checking whether data is in a particular shape, and converting from one such shape to another (including from older versions of a shape to newer versions).
Then I think that's primarily a problem of data from one source that should be interoperable with data from another source? As in: if I control the database and the software interacting with it, then I can simply ("simply") run a migration and update the software. If I control the API and the front-end talking to it, I can update both at the same time, or at least make the front-end able to deal with both the old version and new version without the overhead of adding Dit to my stack. So the use case would be if I don't control both the producer and consumer side of data? And in fact, there might be multiple parties on either side?
If that's the case, then that sounds like the problem the Linked Data community also wants to solve - as far as I know, not extremely successful (but not entirely unsuccessful either). Is there anything in Dit that improves upon a problem that Linked Data is unable to solve?