intranet colaboration system

I would like to give our intranet users and create, edit, colaborate documents via a browser. What is the best way to go about this?

Requirements: The user should be able to:
1. create content,
2. edit content (content created by anyone)
3. records should be kept on who edited what and when
4. should easily be able to go back and forth between edits
5. should be able to assign rights to created/edited pages (i开发者_开发百科.e. who can view them)

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Nearly all Wiki-engines works like that.

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i'd recommend flexwiki, a breeze to install and you can dive into the source code to change what doesn't suit you. it's been out of updates since a while now, but there's only so much you can add to a wiki...

Apart from that, you could use the google apps suite, their collaborative work is really good. You can have them hosted on your servers, but i don't know anything about their pricing and use terms