From the Google Blog:
Google is a company fueled by innovation, which to us means trying lots of new things all the time — and sometimes it means reconsidering our goals for a product. Later this week, we will stop accepting new questions in Google Answers, the very first project we worked on here. The project started with a rough idea from Larry Page, and a small 4-person team turned it into reality in less than 4 months. For two new grads, it was a crash course in building a scalable product, responding to customer requests, and discovering what questions are on people’s minds.
The post eulogizes Google Answers, but doesn’t really explain why Google discontinued it….