Actually, that gives me a sort of unique idea: An online, wikipedia like proof database with understandable informal proofs with click-to-expand (inline) annota

Actually, that gives me a sort of unique idea: An online, wikipedia like proof database with understandable informal proofs with click-to-expand (inline) annotated sections, if you click them, they would expand into proof of less formal claims. The idea would be that we generally share understanding of obvious axioms (and thus, allow them to be request-able assumptions), and so can enhance readability.