I'm working on a list of top 100 enterprise 2.0 links and here's a site that Adam Carson recommended. It's been super helpful in my report on enterprise-grade Wikis that I'm writing.
The link is for WikiMatrix.org. If you haven't been there already its well worth checking out. The site's an uber-database of every Wiki and their features.
So if you were interested in a wiki software that provide page history, WYSIWIG Editing, data storage in a database, and a Plugin system then four products would match up: Clearspace, TikiWiki, WackoWiki, and XWiki. Check out the search results here.
If you wanted a hosted offer with WYSIWYG editing , a page history, uses your own domain, allows your own corporate branding, has ACLs and no ads then these four products appear: BrainKeeper, SamePage, SocialText and WetPaint. The search is here.
Anyone else have similar links for other enterprise 2.0 stuff?