At the company I work for we use a WikiWiki (specifically TWiki, a Perl implementation) as our intranet.

The advantages are that everyone can make changes, but that these are logged and can be rolled back via a version control system. Before making changes, one has to log in so changes can be traced back to the people who made them.

It is used extensively to document the projects we're working on, which is easy since TWiki allows to upload files. People seem to like working with it, so the "threshold" to documenting seems to have lowered ;-)

In my opinion, it would definitely worth having a look at it as part of a solution.

Just my 2 cents, -gjb-