The related keywords tool automatically suggests new keywords, in addition to those set by the advertiser, which will be triggered when an ad is served. Related keywords allows you to 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 the related keywords tool is enabled.
Ads for automatically-added keywords are served on Yandex search results pages and search sites belonging to the Yandex Advertising Network.
The related keywords feature is enabled by default for new campaigns. It can be disabled on the campaign settings page (in the section).