Anybody knows any knowledge base open source? [closed]

Question

How about one of the many wikis?

Kenny: I've used FlexWiki & ScrewTurn (abandoned).

someone else with RepPower to edit my post added this.
Wikipedia is powered by MediaWiki.

I have used phpMyFAQ and found it to be very good.

In addition to MediaWiki that was mentioned by Kenny, you might also look at MoinMoin.

Choosing between MediaWiki and MoinMoin can be a bit tough. Here are some points to consider:

MediaWiki

Pros:

• Made for wikipedia, thus is very mature and scalable.

• Fairly easy to set up.

  Cons:

• Made soley for wikipedia. Thus it can be a bit of a pain to customize how you like it.

MoinMoin

Pros:

• Very mature software.

• Huge amount of plugins and third party modules available.

  Cons:

• Can be a pain to install.

There are a huge amount of other wikis available, but those are the main two I would consider.

Since I don't have enough reputation points to comment on Bruno Shine's answer, I'll add this note as a new answer.

KBPublisher 2.0 is still available on Sourceforge: http://sourceforge.net/projects/kbpublisher/

The project hasn't been updated for years. I've been running it since v1.9 or something, and it works fine.