推荐几个和stackoverflow类似的开源框架，postgresql重度用户建议使用osqa，可以支持问题，回答，comment的中文全文检索。
[转载]http://www.mkyong.com/featured/top-5-open-source-qa-systems/
list of the open source q&a implementation or stackoverflow-like website, with “active” development and promising features and community.
p.s this list is not in any particular order.
website : http://www.osqa.net
demo : http://meta.osqa.net
language : python, django
database : mysql, postgresql or microsoft sql server
license : gnu general public licence (gpl)
source code : http://www.osqa.net/download/
created by : folks at dzone
website : http://shapado.com
demo : http://shapado.com
language : ruby , mongomapper
database : mongodb (document based db engine)
license : gnu affero general public license (agpl)
source code : http://gitorious.org/shapado
created by : david a. cuadrado
website : http://askbot.org
demo : http://askbot.org
database : mysql, postgresql
license : gpl3
source code : https://github.com/askbot/askbot-devel/
created by : mike chen and sailing cai
website : http://www.question2answer.org
demo : http://www.question2answer.org/qa/
language : php
database : mysql
source code : http://www.question2answer.org/install.php
created by : gideon greenspan
website : http://www.lampcms.com
demo : http://support.lampcms.com
database : mongodb
license : gnu lesser general public license (lgpl) version 3
source code : https://github.com/snytkine/lampcms
created by : dmitri snytkine (twitter)