If the intent of this site is to be a Q&A site, primarily for people to ask questions and get responses, and also provide a place where people can view previously asked questions and find answers (a sort of user-generated database of questions with answers), wouldn't it then follow that it is appropriate to ask a question and answer it yourself, even if you knew the answer before asking? Presuming the question was well-stated and appropriate, and the answer was accurate, well-cited, lucid, and accessible, I can't see why this wouldn't be a good thing.
I just thought of it because, in the comments to this question, explaining Kant's theory of causation would be outside the scope of a comment, yet I feel like louzer (and future others who read the question) may want to see Kant's a priori proof of causation. I'm presuming someone will ask it at some point, and sure, then I can provide a clear answer. But in principle, it doesn't seem like it matters who the asker is, only that it's asked and answered in a form that is appropriate for this site. So why not ask it myself right now?
What is the policy for doing something like this?