Abstract: A user provided content provided via the Internet is identified. The user provided content belongs to a previous version content item of a content page accessible via the Internet. A previous version content item identifier for the previous version content item is generated including by combining a content from a title of the previous version content item and a content from a description text of the previous version content item. A new version content item identifier for each content item of a plurality of content items belonging to a new version of the content page are generated, including by combining a content from a title of the corresponding content item belonging to the new version and a content from a description text of the corresponding content item belonging to the new version. Measures of similarity between the previous version content item identifier and each of the new version content item identifiers are calculated.