LampCMS
LampCMS is an full-featured Open Source Question and Answers web program written in PHP with deep integration with Facebook, Twitter, Google, Linked-IN, Tumblr and Blogger APIs It uses MongoDB as a database to achieve speed and scalability.
OSQA
OSQA is the free, open source Q&A system you've been waiting for. Your OSQA site is more than just an FAQ page, it is a fu ...
Askalot
Askalot is a next generation CQA (Community Question and Answer) system.
Question2Answer
A Q&A site helps an online community to share knowledge. No matter what your area of interest, people with questions can g ...
AskBot
Askbot is a Q&A system, like StackOverflow, Yahoo Answers and some others. Askbot is based on code of CNPROG, originally c ...
Mamute
Mamut is a tool that allows to ask questions and give answers and comment on both. In addition users could vote for questions ...