B. Mann Consulting

A "wiki" is more of a collaborative space than a CMS, but it includes some of the same elements. Some more info can be found here, with a short quote:

The concepts behind "Wiki" may seem strange at first, but try it and explore its links. Wiki is a composition system, it's a discussion medium, it's a repository, it's a mail system, it's a chat room, it's a tool for collaboration. Really, we don't know quite what it is, but it's a fun way to communicate