Question2Answer(or Q2A) is a free and open source content management system to create Question & Answer communities like StackOverflow or Yahoo Answers. users can easily ask their questions and get answers from others or engage in questions by answering other questions. Q2A provides high social engagement with comments, voting,following questions, tags and categories, users, and has a powerful points-based reputation system.
not only Question2Answer has all features that you need to build a fully functioning Q&A site, but it can also be integrated with other content management systems such as WordPress to use it's user database and work as a part of it. imaging how you can use WordPress to have blogging, shop, social site on your web site and you can also add a fully functioning Q&A Community to it.
Question2Answer is optimized to provide highest speed and load time. it's also scalable to handle millions of users and posts.
Q2A is safe from hackers, by protecting your site against SQL injection, XSS, CSRF attacks.
Easy to use, easy to set up, easy to configure, and at the same time very powerful.
Users can Ask, Answer, Comment, Vote, and Follow other users, categories, tags and questions.
Q2A offers a solid Point-Based Reputation management system & Badges, inviting users to have more activity.
Build in User Levels, User management and Profiles, notification and privet messages, social login, ....
Q2A is optimized to gain high search engine ranking and traffic as a builded-in feature.
Question2Answer is created to handle any number of users and their activity.
Question2Answer is Free and open source under GPL v2 with an active community
Q2A already has a handful of free and premium themes and plugins.
Q2A can be integrated with any other web platform and work as a part of it. it's also ready to easy WP integration.
Question2Answer is your best option, it is #1 platform to create Q&A websites.