• Shapado (http://shapado.com/)
• OSQA (http://www.osqa.net/)
• Question2Answer (http://www.question2answer.org/)
• Coordino (http://www.coordino.com/)
• LampCMS (http://www.lampcms.com/)
• Stacked (https://code.google.com/p/stacked/)
• Phpancake (http://sourceforge.net/projects/phpancake/)