内部网协作系统

我想给我们的内部网用户,并通过浏览器创建、编辑、协作文档。最好的方法是什么?

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.e. who can view them)