The German Wikipedia was the first language edition to adopt flagged revisions. The system, also called stable article versions or sighted revisions, was announced for the German edition at Wikimania 2006 and went live there in May 2008.
Flagged revisions add an editorial-review layer to wiki editing. Certain trusted users can mark a version as reviewed, indicating that it contains no obvious vandalism. Readers may then see the latest reviewed version while newer, unreviewed edits remain available for inspection. German Wikipedia uses two relevant sighting levels: passive sighters and active sighters.
This feature is often confused with ordinary page protection or with English Wikipedia’s limited pending-changes use. They are related safeguards but are not identical. Flagged revisions became especially prominent in German Wikipedia because the edition uses review status broadly, whereas English Wikipedia has used the extension in a much more restricted way.