Most active that look like the best bets
- shapado Ruby, mongomapper and mongodb. Live site, also provide hosted sites for free. AGPLv3. Seems to be under active development as of June 2010.
- OSQA . Django. Live site. GPLv3. More actively developed fork of CNPROG.
- ASKBOT Django code, docs, import data. GPLv3. To install type “pip install askbot”.
- Question2Answer. Live site PHP, MySQL. Actively developed. GPL license.
- CNPROG. Django. Live site(Update 21/01/2011: link leads to a page which says CNPROG is officially closed). GPLv3. Not a lot of recent activity; last code commit, Oct 2009 (as of Feb 2010). Primarily developed in Chinese, although there are English translations.
Ones that look sort of finished
- openoverflow. Ruby, PostgreSQL, Haml. MIT license. No example site, and I can’t find anyone using this one. Not a lot of recent activity; last code commit, May 2009 (as of Feb 2010).
- phpancake. PHP, Zend framework, MySQL. Live site. MIT license. Last activity Jan 2010. Renders very poorly in some browsers.
- cahoots. PHP, MySQL. GPL, MIT license. Officially inactive; demo site offline; last update Aug 2010.
- Qwench PHP. Example site (no pages except question list). No activity since Dec 2009.
- soclone. Django framework. MIT license. Seems to have gone stale in Nov 2008 (and only started on Google Code at the end of Oct 2008).
- Plurk Solace. Python. BSD license. No example site, and I can’t find anyone using this one.
- stacked ASP.NET, Ra-Ajax, ActiveRecord ORM. GPLv3. Live site. Seems to have gone stale in Jun 2009. Some legal issues, but they seem to be over now.
- Qanda PHP, MySQL, MIT. Repository. Site inaccessible.
Others that seem to be work in progress
- FortyTwo. Python, Django, CouchDB. Example site. Unknown license. Little info.
- kerjakelompok. No example site. Unknown license. Little info.
- SmartR. No example site. Unknown license. Little info.
- Stack Underflow. C#. No example site. License is “do whatever you want with it” (I haven’t defined a formal license yet). Written as a learning project.
- T002_rails-overflow. Rails. No example site. Unknown license. Little info. Apache license.
- LampCMS PHP 5.3, MongoDB LGPL 3 License
Sorted by language
PHP
Python
Ruby
ASP.NET
- stacked ASP.NET
C#
Unknown
Did I miss any? Disagree? Please add a comment or update this answer.
And I don’t really want to get into listing clones, but I have just come across Answer Bag which seems to be an all-encompassing clone covering everything from aviation through programming to religion. Or maybe that was there first? And Just Answer is another…
