Question2Answer (Q2A) is a popular free open source Q&A platform for PHP/MySQL, used by over 16,000 sites in 40 languages.
Q2A is highly customisable with many awesome features:
- Asking and answering questions (duh!)
- Voting, comments, best answer selection, follow-on and closed questions.
- Complete user management including points-based reputation management.
- Create experts, editors, moderators and admins.
- Fast integrated search engine, plus checking for similar questions when asking.
- Categories (up to 4 levels deep) and/or tagging.
- Easy styling with CSS themes.
- Supports translation into any language.
- Custom sidebar, widgets, pages and links.
- SEO features such as neat URLs, microformats and XML Sitemaps.
- RSS, email notifications and personal news feeds.
- User avatars (or Gravatar) and custom fields.
- Private messages and public wall posts.
- Log in via Facebook or others (using plugins).
- Out-of-the-box WordPress 3+ integration.
- Custom single sign-on support for other sites.
- PHP/MySQL scalable to millions of users and posts.
- Safe from XSS, CSRF and SQL injection attacks.
- Beat spam with captchas, rate-limiting, moderation and/or flagging.
- Block users, IP addresses, and censor words
Q2A also features an extensive plugin system:
- Modify the HTML output for a page with layers.
- Add custom pages to a Q2A site with page modules.
- Add extra content in various places with widget modules.
- Allow login via an external identity provider such as Facebook with login modules.
- Integrate WYSIWYG or other text editors with editor/viewer modules.
- Do something when certain actions take place with event modules.
- Validate and/or modify many types of user input with filter modules.
- Implement a custom search engine with search modules.
- Add extra spam protection with captcha modules.
- Extend many core Q2A functions using function overrides.
As of version 1.6.3, all development is taking place through GitHub. The collaborative development process is being managed by Scott Vivian. (Note that official releases are still distributed via the Q2A website.)
Please read the contributing page for more information on how to get involved.
Thanks and enjoy!