The FAI wiki is built on Atlassian Confluence. Confluence is an enterprise wiki which enables groups to quickly collaborate on projects online.
The essential features of a wiki are that pages are designed to be easily editable, and a historical record is kept of all changes. The assumption is that the more people who have edit permissions the better because there is then a greater chance of information being loaded into the wiki and being accurately maintained once it is there. Stacked on top of that are lots of additional features, for example logged-in users can create personal RSS feeds or email notifications for when content is added or changed.
Confluence is organized in spaces. Spaces are indicated in the menu on the left by a globe icon. Spaces are organized by FAI commission. A main commission space may have an unlimited number of sub-spaces.
Confluence is also organized to have users and groups. Users log in, and the wiki knows which groups they are a member of.
Permissions to view, create pages, edit, administer Etc. are organized by space and user group.
Users who are members of a group with permissions to edit pages in a space can do this very easily using an online WYSIWYG editor, or a wiki notation editor, or an 'edit this page in Word' feature.
There are several kinds of page in a space; the basic page, a news (or blog) item, a comment, an attachment to a page.