Well, the hope was that Watson, having explored and built a connected knowledge graph from various sources, could ask probing, adaptive questions to find out where a person landed.
So, say I'm an undergrad at a good university and I tell the system "I'm interested in Computer Science. I am particularly interested in Scientific Computing and would like to get to a graduate level of knowledge."
The system might ask "Sort the following operations by their worst-case run-time...". Then, if they do well there, maybe "Which of these two examples of auto-parallelization using Matlab's parfor would fail to parallize the code.." or something like that. Over the course of so many questions, the system would start to paint a more and more reliable picture of where contours of a person's knowledge.
This is time-consuming, of course, but over time it would get easier and faster to find contours by using the 'average' of people with similar backgrounds as a starting point.
Once a fairly good mapping is done of the person to Watson's cognitive model, Watson would need to trace back to the source(s) of nearby concepts and offer them to the user, which, ideally, are then rated by the user for relevance and perceived difficulty to further refine the person's model and rank the material offered for that particular profile.
Now imagine a Grad Student asking a similar question. Or a middle school student. What would those interactions look like? The mappings? The suggestions?
Don't get me wrong...mapping a person's knowledge space is a Very Hard Problem. Watson takes a kitchen sink approach that just isn't possible for a human being. And maybe it wouldn't be possible to tease apart the resulting cognitive model into tidy nodes enough to map anything to. These were questions I'd hoped that IBM could help answer. Instead, it was on to the easy, well-understood problem and solution.