Pages which are fully protected can only be edited or moved by sysops. They may be protected for reasons including but not limited to the following:
- Pages in the MediaWiki namespace are protected by default, for several reasons:
- Many messages are in plain HTML, hence users could insert malicious scripts,
- Vandalism of some messages would be extremely disruptive, for example changes to the text of the links in the sidebar would immediately be visible to all users,
- Navboxes, Amboxes, nesting tricks, and other high-risk templates are protected from vandalism for the same reason.
- A few messages can cause the software to stop working if they are changed.
- Protecting the Main Page from vandalism.
- Maintaining the integrity of the copyright and license pages.
- Maintaining the integrity of past press releases.
- Protecting certain "system administration" pages.
- Enforcing a "cool down" period to stop an "edit war," upon request. In such cases, protection is not an endorsement of the current version and any changes to be made should be discussed on the article's talk page.
- Protecting a page that has been a recent target of persistent vandalism or persistent edits by a banned user.
- Preventing changes to a page while investigating a possible bug.
Pages which are semi-protected may be:
- Fully protected from being moved but not protected from editing.
- Protected from editing by unregistered or recently-registered users.
Reasons for semi-protection include:
- Preventing the addition of vandalism or fanon to an article from anonymous users.
- Preventing anonymous or potential sock puppet votes (as in the case of featured article nominations).
Move protection prevents an article from being moved.
- Protection from being moved, but may still be edited.
- Access can be restricted to registered users or administrators.