Sabai Discuss is a premium questions and answers plugin for WordPress. The plugin features the ability for users to ask and answer questions similar to Stack Overflow or Yahoo Answers.

Sabai Discuss is an ideal tool not only for building a community driven question-and-answer website but also for building a discussion forum, a knowledge base, or even a helpdesk portal for WordPress.

Features
Fully responsive and flat design
Search questions and answers by keywords and category with user friendly auto-suggestion features
Filter questions and answers by custom fields
Create search and filter forms with visual form editor
Post questions and answers from the frontend
Post comments to both questions and answers
Post and edit comments inline
Tag questions with auto-suggest
Hierarchical categories
File attachments to questions and answers
Vote for questions/answers/comments both up and down
Close/reopen questions
Featured questions
Flagging questions/answers/comments with automatic spam moderation
Favorite questions and answers
Accept answers
User profile pages
User reputation system
Custom fields with visual form editor (Choice, Date, HTML, Markdown Text, Number, ON/OFF, Paragraph Text, Single Line Text, CAPTCHA, User, Section Break, File Upload, Image Upload, Video, Email, Phone Number and more)
Role/Reputation based permission system with over 40 permissions to configure
Restrict access to members of selected roles
Allow guest users to post questions/answers as well as accepting answers posted to their questions
Install multiple instances of SabaiDiscuss (by just copying 1 file and a few clicks!)
PHP Markdown editor for posting questions/answers and editing tag descriptions with live preview
Filters user HTML using HTMLPurifier for additional security
Code syntax highlighting using Google Prettify
Search questions and answers
CSV Importer/Exporter
5 shortcodes
9 WordPress widgets included
Template files your theme can override to customize display
10 email notification templates
Works with any theme
Appropriate use of Ajax to improve page responsiveness
Fully translatable
RTL language support
Automatic updater (no FTP required to update the plugin)
Integration with point system of MyCRED and Cubepoints plugin
French (by nexia) translations included