...
* secure - ( need specific questions, test drives )
* do they allow anonymous users, at least for browsing?
CHALLENGES
* authentication and user management - can we avoid each site admin having to add and manage users?
...
Hosting Chit Chat - forums for web hosters; might have some interesting threads
NOTES ON PACKAGES
Geeklog
Plugin developers handbook: http://wiki.geeklog.net/wiki/index.php/Plugin_Developers_Handbook
ActiveCollaboration:
Drupal:
Includes collaborative "books", which strikes me as a somwhat structured wiki.