We've implemented plain old MediaWiki in our division. It serves as a document and guidance distribution point to the wider corporate public, as well as an scratch pad for internal procedures and process. Due to the general lack of fine-grained access control and segmentation, we stood up two instances: one for the "public" site without authentication for read-only access (and mediawiki accounts for division members only to edit content) and another one for the "private" site with HTTP authentication for the wiki root.
Yep mediawiki is great, exports xml. We integrated this into madcap flare and our build. Published (goes to customers) chm, pdf and webhelp takes the latest snapshot and merges it in, internal users can grab the latest by browsing the wiki.
We have a backing internal discussion board for people to discuss training/presales/help and the like which is good for identifying gaps in the doco as well.
