Search Ads 360 overview
A placeholder keyword is a keyword in a search engine account or "other" engines account that provides Search Ads 360 with the information it needs to track visits. After you create a placeholder keyword, you manually copy the keyword's tracking information to the engine. When your customer clicks an ad or other targeting item in the engine, Search Ads 360 collects data about the visit and redirects the customer to the ad's original URL.
For example, you can use a placeholder keyword to report on placements on the Google Display Network, or report on ads in engines that Search Ads 360 doesn't support.