Why?

1. All topics begin with the word 'why'. As one types in the rest of the sentence parses a 'question tree' on a specific question. e.g. 'why do humans yawn?', 'why does democracy not work as expected?' etc. All questions are simply structured: 'why' + [verb] + [subject] + [verb] + [...] is a structure example.
2. Answers are ranked by the community just like in www.stackexchange.com or www.biostars.org.
3. Some people qualify as experts once their credentials are verified.
4. A way to link questions so that one can find related 'why' questions.
5. Perhaps have one for 'what', 'where', 'who', 'how'.