Page validation is the process of Editors reviewing an article or an article's revision to see if it is accurate and satisfies the wiki's quality standards. On reviewing the page is usually given a quality assessment which readers can see in the article's history page. Reviewed revisions of articles are marked as "sighted" or as a "quality revision". This allows the reader to be sure that the article is factual.
In order to mark revisions as quality revisions, the user needs to be part of the Editor user group. You can see the list of Editors at http://wiki.metin2.co.uk/index.php?title=Special:ListUsers&group=editor