When I first used SO for asking a programming question, I remember getting answers that would solve my problem, but that I would not totally understand because the answer was out of the scope of what I had to that point learned (as I'm still a student of programming).
Also, when answering questions, it's hard sometimes to get an idea of what the OP (if student) has already learned. I think it is a little easier for a student to gauge the level of knowledge of another student because the topic path is still sort of fresh in their minds. For example, if I see a question with repetitive code, that could easily be implemented with a loop, I'd assume the OP has not learned about loops yet.
So my suggestion is maybe to come up with some sort of system to gauge the OP's knowledge or possible make it a standard for the OP to elaborate on their knowledge and what they've learned so far.
It seems like a stretch, but I think it would make the student's learning process more efficient. But who am I to say anything, I'm still a newb :)