Yahoo! Answers and StackExchange are two well-known examples of Q&A sites. Both sites allow users to ask questions, vote, and choose the best answer. Both sites have a point system to encourage their users to give useful answers. Yet they are at the opposite ends of the quality spectrum.
I often wondered if the UI may play a role in the type of content a site attracts. Maybe certain layouts or UI features are subconsciously more appealing to, and hence attract more of, the technically-inclined subset of internet users, which might in turn lead to more high-quality content. Maybe other aspects in the UI design play a role, too.
Is there anything (on the UI side of things) that can encourage quality content?