Question2Answer

A social Q&A site encourages your online community to share knowledge and helps create content that is very search engine (SEO) friendly. Question2Answer is a free PHP/MySQL solution for social Q&A sites (like Stack Overflow or Stack Exchange) with the following features: • Five minutes (or less!) to install. • Easy styling with CSS themes. • Fast integrated search engine. • Points-based reputation management. • Categories and/or tags (with auto complete). • Email notifications and RSS support. • Voting, comments and follow-on questions. • Simple and secure admin interface. • PHP/MySQL scalable to 1,000,000+ posts. • Built-in user account management, or... • Single sign-on for existing sites.