My startup idea is a questions and answers website for user interface design.<p>I'm aware there is a stack exchange for programming and ux, but there isn't one specifically for user interface design.<p>How many of you can see yourself actually participating in a Q&A site about UI design? Would you ask and answer questions?
Problem is with UI design q&a site is if there is a demand for it, it wont be long before StackExchange puts competition up. It would take minimal effort on their part, that's your main risk.