For smaller windows-only companies I've recommended OneNote on a fileshare. It is really simple, everyone who can use Word can use it. It is also very wiki-lik

For smaller windows-only companies I've recommended OneNote on a fileshare. It is really simple, everyone who can use Word can use it. It is also very wiki-like in that it is quick to edit, searchable (and fast), versioned and it is easy to see when something has changed (bold tabs). Personally I used to prefer dokuwiki (and before that I made a custom tool in Javascript to simplify use of mediawiki to document procedures.)