What is the difference between AFS, RSOC and AFD?
AFS, AdSense for Search, puts Google ads on a site's search results page. RSOC, Related Search on Content, is an AFS feature that adds suggested searches to an article and leads into those results. AFD, AdSense for Domains, put similar ads on parked domains with no content, and Google retired it as an ad surface in February 2026.
Picture three shop fronts selling the same goods. AdSense for Search is a shop with a counter: the visitor asks for something and is shown ads. Related Search on Content is a magazine rack by the door that suggests what to ask for. AdSense for Domains was an empty unit with only a list of suggestions in the window.
For operators the differences are practical. RSOC needs genuine content, account-manager approval and the referrerAdCreative parameter. AFD needed only a domain, which made it easy to scale and hard for advertisers to value. That is why Google gave advertisers an advertiser opt-out, then opted everyone out by default. Today "Google search arbitrage" effectively means RSOC on AFS.