Listed here are clones of the Stack Exchange sites model.
Stack Exchange has released an updated, feature-complete version of the Stack Overflow engine which is now available for enterprise use. You can read more about that here
but if that does not meet your needs, there are several third-party tools that try to clone at least some of the functionality here.
Most active that look like the best bets
Not open source
AllAnswered: Django. It allows any community to create their own Q&A site. Free.
Haydle: SaaS, free 30 day trial. Haydle is focused on being a private, internal Q&A system.
Rootbuzz: Django, hosting, actively developed, non-free
SabaiDiscuss: commercial WordPress Plugin
Programlama: Python, flask (In Turkish)
Unity Answers: Allowed topics are the Unity editor and C# (the site is free and in English)
Ones that look sort of finished
OSQA: Django. Live site. GPLv3. More actively developed fork of CNPROG. OSQA is in maintenance mode, with security and Django platform updates, but few new features. AnswerHub has replaced OSQA as DZone's primary Q&A solution.
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.
cahoots: PHP, MySQL. GPL, MIT license. Officially inactive; demo site offline; last update Aug 2010.
stacked: ASP.NET, Ra-Ajax, ActiveRecord ORM. GPLv3.
Others that seem to be work in progress
Asking: Perl, Mojolicious. Perl License (Artistic). Little documentation at this point. GitHub repository README.md in Portuguese.
kerjakelompok: No example site. Unknown license. Little info.
SmartR: No example site. MIT 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: Ruby on Rails. No example site. Unknown license. Little info. Apache license.
CNPROG: Python/Django.Project officially closed. Was used as base by OSQA & Askbot.
Sorted by language
- Q&A (Is a WordPress Plugin)
- Vanilla Forums
- openoverflow (last commit in 2009)
- T002_rails-overflow (last commit in 2009)
SmartRCreator announced it is deprecated.
- QARoR (barely any progress)
- Discourse (active, primarily a discussion forum)
MEAN (MongoDB, Express, AngularJS, and Node.js)
Did I miss any? Disagree? Please add a comment or update this answer.
Stack Overflow clone in PHP -- "Qwench"
- project forums
www.qwench.net (parked domain)
- live demo at
Inspired by Stack Overflow: http://www.iFixit.com/Answers
Jeff Atwood mentioned them in one of the Stack Overflow blogs, Our Sidekick, iFixit.com, although he got it wrong. http://ifixit.com has been around for a while (2003 http://en.wikipedia.org/wiki/IFixit), while Answers had recently been released.
Here's another, called Verious.
Update: As of today May 9, 2017, this site has been dead for some time and is now gone from the internet.
There is also MetaOptimize's community QA site. It is clearly based on the SE model in its design, style, functionality, etc. It's content is a mix of Stack Overflow programming questions and Cross Validated machine learning & data visualization questions, with perhaps bits of other SE sites thrown in. Their self description is:
Where scientists ask and answer questions on machine learning, natural language processing, artificial intelligence, text analysis, information retrieval, search, data mining, statistical modeling, and data visualization!
The design is almost identical. Just replace
tags. They even have diamond mods and green boxes for accepted answers!
A user profile:
Update: As of today (May 9, 2017), the site has been dead for some time and is now gone from the internet.
Quick Answers at Code Project: http://www.codeproject.com/script/Answers/List.aspx
While digging for an answer to this question myself, I found that http://ask.sqlservercentral.com is not affiliated with Stack Exchange (but it does a fine job of ripping off the look and feel of the site):
Quote from Dumb question of the day
I can clarify that OSQA is a completely different Q&A community system than StackExchange. A month or two ago, Joel Spolsky announced that StackExchange was shifting direction and that the planned hosting model for StackExchange would be eliminated. We (the folks in the open source OSQA project) offered to help the soon-to-be homeless communities by helping them migrate to our system.
Red Gate contacted us about this offer, so we set up a demo site with the AskSSC community data. A while later they came back with some questions, which we answered, and they chose to go forward with the migration. We implemented the switchover this past Friday in order to have the weekend as a slow time to spot and fix any kinks in the live site.
There is no connection between StackExchange and OSQA. OSQA was originally based on a Chinese-language StackOverflow clone project called CNProg, but that original code has been almost completely eliminated and rearchitected. Going forward, I hope you'll see that OSQA is a verstile, reliable and useful system for hosting a Q&A community site like AskSSC. The StackExchange folks have made clear that their current version is a dead-end street and that no new development will be done on it. Their new business model doesn't accommodate sites like AskSSC, so staying on StackExchange really isn't a viable long-term option.
I'm sorry to learn that many in the AskSSC community were unaware this change was being considered, but I hope you'll all understand what took place. IMO, the Red Gate team was faced with a tough reality that was beyond their control. Having built a lovely community in conjunction with so many knowledgeable SQL Server experts, the rug was pulled out from under their feet. Granted, it would have been better if the migration had been more widely discussed and anticipated, and fewer community members would have been taken by surprise. Still, I hope the choice to use OSQA proves to be a good one and that the community will understand and support it.
FWIW, you should know that the OSQA developer team is deeply committed to helping this site and community thrive. OSQA is genuine open source software, and we are not being paid a penny for our work. We just want to continue evolving OSQA into a truly best-of-breed solution. We're probably insane, but we really do want to help.
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protected by Community♦ Sep 22 '11 at 22:37
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