Protected pages is a facility which can enable restricting privileges of two distinct functions of wiki pages; namely edit protection, and move (or page rename) protection. Each function area has one default level, along with two escalating levels of restriction or protection: (a) allow all users (b) allow only autoconfirmed users, and (c) allow only administrators.
for editing function
- a./ allow all users — this is the fundamental and basic operation of a wiki; typically known as an 'open edit' wiki, this allows not only registered members of the wiki to edit pages, it also allows those who have not registered to edit, and these latter group are known as IP editors
- b./ allow only autoconfirm users — effectively means blocking unregistered users, (IP editors), and also affects registered users who have 'logged-out'; and therefore means that only registered users can edit that particular page
- c./ allow only administrators — this means that only users with system operator (aka 'sysop') access levels can edit. Click here for a list of such people.
for move function
These will be listed under the identical options as for the above editing function. There are, however some subtle differences.
- a./ allow all users — similar to the above editing function, this setting will allow unregistered IP editors to rename pages; in reality, many MediaWiki sites will disable this aspect as a global wiki-wide default – meaning only logged-in registered users can move pages
- b./ allow only autoconfirm users — again, same as the corresponding edit function level protection, this restricts page renaming to logged-in registered users and prevents IP editors from carrying out this function
- c./ allow only administrators — as above, this means that only sysops can move or rename the page.
It will be noted that when a specific edit level restriction is set, the move protection will be set at the same level (unless specifically changed to a higher level), and can not be set to a lower level. That means that if edit protection for a page is set to only sysops (c above), then move protection will also be only sysop, and move protection can not be set lower. It is also possible to set pages with higher levels of move protection whilst still allowing unrestricted free editing of the page.
Reasons for, and consequences of page protection
Some pages are protected because they are constantly recreated.
Pages should only be protected as a last resort to stop an edit war or chronic vandalism, or to prevent vandalism of high-visibility and/or high-importance pages, or those which seem to be repeated targets of spam. If semi-protection (ie, level b) will suffice to stop the edit war or vandalism, then it should be used. Protection duration should only be indefinite for high-visibility or high-importance pages.
It also generally recommended to protect certain very specific pages which arn't usually subjected to spamming or vandalism. Typically, infobox templates (along with any cascading templates they rely on) which are used on substancial numbers of pages on the wiki should be protected; as any changes to them (irrespective of those edits being necessary, good faith 'good' edits, or bad edits such as spam or vandalism) can place great loading on the server holding the wiki database.
Even more caution, by means of the most strongest protection should be applied to templates which use semantic data on wikis which also use the Semantic MediaWiki plugin extensions; as unlike general wikis not using semantic data, whereby undesirable edits can be [[revert]ed without leaving any lasting damage to the wiki (save for the fresh increased server load), on semantic data wiki, any change to semantic data properties will be permanent, and in some instances can severely damage semantic data output.
Finally, all users of the wiki, including IP editors can check the protection status of any wiki page – simply by clicking on the 'edit' tab at the top of each page (or any of the section heading  areas), and the protection status – if any, will be shown in a banner at the top of the page.