The amount of publishing control a visitor to a wiki will have depends on how the wiki administrator has set up the software. In general, the wiki administrator can make changes to the user interface of the wiki. This might include different wiki themes, the navigation and other customization features. This is usually on the outside or around the main text of the wiki. The inside area, or the area where the main content is located is often set-up so that others can edit and add content to the wiki. Publishing controls can take many different forms, here are a few examples:

Personal Publishing: A wiki can be used as a personal brain dump, where one user (the wiki administrator) has access to the wiki and everyone else becomes a viewer of the content.

Group Publishing: A group of people have access to the wiki - usually done through user-names and/or passwords that are given out by the wiki administrator. Few have access to edit, change and add pages on the wiki, but all can view.

Public: Changes can be made by anyone who visits the wiki, changes and additions are monitored by the group as a whole. A good example is wikipedia. This type of permissions allow you to collaborate with the world.

Private Wikis Wikis may be used for a number of different purposes which limit access to the wiki. For example, if the wiki is located on an intranet you are automatically limiting access to the wiki. Access may also only be granted with username/password to all of the content of a wiki - (PBWIKI example set to private) Or you may not want to have contributions from anyone else, but a select group of people.