AdvFAQs is an application that allows users to answer your questions. You can create categories and create FAQs to resolve user concerns. It also has a rating system, where the most useful questions will appear on the homepage.
In this version, users can register and make their own inquiries and other members resolve their doubts.
Demo page: http://demo.pri.pw/demo1/
Demo account: demo@demo.com
Demo password: demodemo