Well, there's LibStats:

It's open source and functional, but showing its age and feature poor 
compared to commercial projects.  For example, it's primarily designed 
for tracking questions for statistics and reporting purposes, rather 
than building a knowledge base.  It does have the ability to search past 
answers, but that's not quite the same.

It also seems to be unmaintained. So your mileage may vary.

Will Martin

Web Services Librarian
Chester Fritz Library
University of North Dakota

On 2014-09-12 09:41, Kim, Bohyun wrote:
> Hi all
> Does anyone have a suggestion for the free open-source Q/A board +
> easily searchable KB comparable to LibAnswers? We already have
> LibAnswers for patrons. This is more for the library staff who submits
> a lot of similar or same questions to the Library IT help desk.
> It is an option to use the SharePoint Discussion Board but I am
> looking for an alternative since SP tends to get lukewarm responses
> from users in my experience.
> Any suggestions or feedback would be appreciated.
> Thanks,
> Bohyun