Ton Zijlstra suggests a portal concept for work groups to cllaborate and exchange. His idea utilizes two weblgs, a wiki with an internal area and a discussion board. Ton patches together several tools for this (a Wikka Wiki, two WordPress blogs and a Simple Machines forum). That’s a way to go with almost no server administration involved: just using tools available on the net today. And it could be started right away by anyone.
I think that Plone just is the almost perfect tool for this. It allows to insert several blog and wiki instances within a Plone instance. Also, read/write access permissions are extremely fine grained, so every imaginable constellation of access rights could be implemented.
The problem with Plone: ZWiki is not as powerful as some other Wiki engines out there yet (well, it is, but you’d need to dig deep into it), CMFboard is just not as bugfree as other examples around and finaly Quills is a blog tool that misses some features and the funtionality of tools like WordPress. Last but not least: the skinning system of Plone is ultra-flexible but then very hard to control.