I don't think an answer has to be specific to be useful. Often just understanding how an expert in a certain area thinks about the world can be useful even if you have no specificity.
When it comes to questions: 1) What was the greatest discovery in your field in the last 5 years? 2) Is there an insight in your field that obvious to everyone in your field but that most people in society just don't get?
r/Fitness does a weekly "Moronic Monday", a judgment-free thread where people can ask questions that they would ordinarily feel embarrassed for not knowing the answer to. I thought this seemed like a useful thing to have here - after all, the concepts discussed on LessWrong are probably at least a little harder to grasp than those of weightlifting. Plus, I have a few stupid questions of my own, so it doesn't seem unreasonable that other people might as well.