What does AFS stand for?
AFS stands for AdSense for Search. It is Google's product that lets a publisher show Google search ads on its own search results pages and share the revenue. In search arbitrage, AFS is the engine behind the results page a visitor sees after clicking a related search term. It is also called Custom Search Ads or simply Search ads.
AdSense for Search has been part of AdSense since the 2000s. Its original purpose was site search: a publisher adds a search box and Google places ads beside the results. The ad unit was long known as Custom Search Ads; in November 2024 Google's policy pages switched to the plainer name "Search ads".
In the same update, related search for content pages became a "product-integrated feature" of AFS with its own policy set. So when operators say they "run AFS" they usually mean the results page, and when they say "RSOC" they mean the related-search unit that feeds it. In April 2025 Google also ended AFS support for mobile apps.