There is currently a war going on, in the wiki communities, between individuals who want to invite others to collaborate in building a body of information pertinent to a topic, and greedy, selfish individuals who want to pervert any sort of public medium to line their pockets, protect their egos, etc.
While there are many interesting partial solutions against ad spammers and trolls, none of them are quite as effective as simply annotating changes with the name of the individual who made them. If an individual begins to pose a problem, they can be removed from the system. Criteria for admission, like captchas, email address verification, IP black listing and others provide a barrier of access for casual automated attacks, while the concepts of user identity, user sponsorship and social worth can either make the hotheads consider their position, or allow administrators to bar their access.
The Cloud Wiki Manual restricts itself to a few users, as a defensive measure against crapflooders. It is used more like a content management system by its owner than a traditional freeform wiki, like C2 Wiki. Kabuki Wiki borrows authentication from its Kabuki Server chat server, with the theory that only Kabuki users should be editing there, anyway. (And I can beat individuals who abuse the system bloody in the next RPG session. <wink> )
For diehards and individuals who will be using Cloud Wiki behind a firewall or some other form of protection from malicious editors, Cloud Wiki can run in a traditional anonymous mode, simply by setting site-auth to "none".