what is unity answer's software?

i want to create a web site like unity answers for Iranian users of unity. the site will use our local language for farsi users. i want to know is there any open source or free software like unity answers or stackoverflow to set up in our server?

The software is Stack Exchange (http://stackexchange.com/) by Fog Creek Software.

Using the open-source Drupal web content management system, you can construct a site with the same basic idea as the Stack Overflow Platform:

  • Set up a basic Drupal forum.
  • Use the Vote Up/Down module to allow users to rate questions (forum posts) and answers (comments on forum posts).
  • Use the Userpoints module to handle user reputations, and Userpoints Karma to cause votes to affect user reputations.

(Or check out this tutorial for another approach.)

UPDATE: I recently published a Drupal module that sets this up automatically --- http://drupal.org/project/atrium_answers

Second update: Unity Answers has switched from Stack Exchange to Qato.

Shapado looks like it might fit the bill for what you're looking for.

Hi, I'm one of the main developer of Shapado, you can contact us in #shapado on freenode or by email to shapado -at-/ ricodigo d0t com. We are completely free and open source, and the software is available in various language such as Spanish, Portuguese and French and it can be easily translated into other languages. You can check us out here or grab the code here gitorious.org/shapado

See Are there any clones/alternatives for running a Stack Exchange style Q&A site? - Meta Stack Exchange

As for what this site specifically runs on: Based on the link at the bottom of this site, it looks like Unity is paying another company to host free software for them.

there are some free question and answer sites available. some of them are made with python and ruby and some others with php and mysql. question2answer.org is the only php based if you need one but shapado has the most features and will be sponsered by google's summer of code.