Related keywords are keywords which are automatically added to keywords that were set by the advertiser. Related keywords allow you to top up your campaign with new keywords and as a result increase your target audience without wasting time on selecting keywords.
Related keywords works well with popular categories. Examples of such categories are selling clothes or furniture. In highly-specialized categories (such as uncommon products and services), the system will require time to select the appropriate keywords. Sometimes keywords may not be selected, even if related keywords is enabled.
Ads for related keywords are served on Yandex search results pages and search sites belonging to the Yandex Advertising Network.
Related keywords are enabled by default for new campaigns. You can disable them on the campaign settings page in the Keyword optimization section.