TinyWiki has some lessons here. It was created to house Perl Design Patterns, so the end goal is a book-like document. Like a Wiki or like the Everything Engine, it is composed of nodes. The standard Wiki idiom of category membership was barrowed, to good effect. The original Wiki, Ward's Wiki uses this. Wiki automatically creates links at the mention of a known compound word, and Wiki will tell you all of the pages linking to a page. By linking to a category index, people may link back from that category index to everything that links to it.

TinyWiki has an assemble.cgi script that attaches all referenced nodes from one node to the end of that node. Essentially, the starting node is the table of contents for a book, or a chapter, or some other document. It has no role but to list which nodes, and in which order, nodes should compose a book.

Recent edits has proven critical for Wikis as well. TinyWiki's lists all nodes last edits. This lets maintainers work both directions - update the least recently edited nodes and the most recently edited nodes - to bring things up to date or refactor them, and to answer questions and check peoples editorial work.

Refactoring is important. It is vital. An old page that duplicates the contents of a newer page may have the newer page merged in, or it may be merged into the newer page. Things are transient in a Wiki. Nothing is permenant. People contribute knowing that eventually their ideas are just fodder for something larger. In terms of an information system, redundancy is bad.

Cross referencing. Each new node links to related nodes by mention of keywords, but it requires attention from people who know their way around the site to edit old and new nodes and improve this cross referencing. If nodes don't link to related nodes, navigation is impossible. I find browsing Wards Wiki a great way to pass time, but leaving the beaten path of the home page on PerlMonks, and you're instantly in no-mans land.

Mechanisms help the process, but ultimately it boils down to, as Ward puts it, careful attention to detail.

-scott