One of the fundamental rules behind the Wiki is to make things really simple. Webs such as the original Wiki by Ward Cunningham and MiniWiki take this to the extreme. There are few rules, and the rules that are around are easy to pick up and enforce.
Wiki sites put little time into initial design. Because it's so easy to add another page by adding the  brackets around a word or group of words, it's easy to rearrange the comment. If a page starts to get too big... just move a block of content that has a similiar theme to a new page. For example, don't start thinking about how to categorize your links if you haven't started adding them yet! Once you have a dozen actually added, it'll become much more apparent on how they should be divvied up.
New to the idea of Wiki? Head over to the original WikiWiki web and read there information on the topic: http://www.c2.com/cgi/wiki?NewUserPages
So, one of the fundamental necessities behind Wiki is the need for continual cleanup, continual refactoring, continual reform. Is any content editor capable of this? is any reader capable of this?
Fozbaca and I have talked about this before... It seems like people who are used to refactoring all the time (e.g. programmers) are the people most capable of this. It is unfortunate.
WikiSubWebs discusses the practicality of having sub webs (such as Twiki does). It does not make sense to use them on a site such as Nyetwork that focuses on useful, practical, and high quality content.
See the list of other Wiki clones