Quora
Free
Quora is a question-and-answer site where questions are asked, answered, edited and organized by its community of users.
AskBot
Freemium
AskBot is a Django/Python Q&A forum.
OSQA
Open Source
OSQA (Open Source Question and Answer) is an open source question-answer system written in PythonLearn More with Django.
Question2Answer
Open Source
Question2Answer is a free and open source platform for Q&A sites.
Yahoo! Answers
Free
Yahoo! Answers is a community-driven question-and-answer (Q&A) website.
Compare Stack Overflow with alternatives
Compare Quora and Stack Overflow and decide which is most suitable for you.
Compare Question2Answer and Stack Overflow and decide which is most suitable for you.
Compare AskBot and Stack Overflow and decide which is most suitable for you.
Compare Yahoo! Answers and Stack Overflow and decide which is most suitable for you.
Compare OSQA and Stack Overflow and decide which is most suitable for you.