Could we use the data dump that stack exchange publishes for theoretical computer science and create an ontology out of it? The data is heavily structured and the things I can think of what we could do with it.
Create robots that aid in question answering
Machine learn what kind of questions are asks and who asks them
Learn more about theoretical computer science sociologically
The things that help us are as follows
Everything is ordered and tagged by humans
It will be constantly changed and updated
The problems with it are as follows
Knowledge engineering these types of questions is hard by definition (some questions have no answer or can't be answered!)
The strategy I thought of would be to go for the "easy" questions first (questions tagged as off topic) and work from there.
I am not sure what you are suggesting here. If you want to build a system like that, then I agree with Suresh: go for it, data is available. If you want someone to build it, then my guess is that things like this will not happen unless you already have something to start with or you are extremely lucky.
Note that most closed questions have no answers and zero or negative score, and such questions are subject to automatic deletion. This means that closed questions in the data dump do not probably reflect typical closed questions, unless you take the union of multiple data dumps.